Serum procollagen type 1 amino-terminal propeptide (P1NP) as an early predictor of the growth response to growth hormone treatment: Comparison of intrauterine growth retardation and idiopathic short stature.

There is no way to predict early the growth response to growth hormone (GH) treatment in short children with intrauterine growth retardation (IUGR) or idiopathic short stature (ISS). OBJECTIVE: To evaluate the capacity of the procollagen type 1 amino-terminal propeptide (P1NP), a new marker of bone formation, to help in this prediction. PATIENTS AND METHODS: Longitudinal study of 30 patients treated at 7.7 (range: 2.2-12.5) years for IUGR (n=16) or ISS (n=14) with GH (0.47 and 0.33 or 0.4mg/kg/week respectively). P1NP and insulin-like growth factor I (IGF I) were measured before and after 3-6 months of GH treatment. RESULTS: Before treatment, IUGR patients were younger and shorter than ISS patients, but their other characteristics were similar. IGF I Z-score (ZS) and P1NP concentrations were positively correlated in the whole population (Rho=0.48; P=0.01). After 3-6 months of treatment, both concentrations increased in IUGR and ISS (P<0.01). They remained correlated only in ISS (Rho=0.54; P<0.05). P1NP before treatment was negatively correlated (Rho=-0.67, P=0.015) with the growth rate (SD) during the first year of treatment in ISS but not in IUGR; IGF I ZS was not. The changes in P1NP for the whole population over 3-6 months, but not the changes in IGF I ZS, were positively correlated with the growth rate (Rho=0.41, P=0.03). CONCLUSIONS: Lower basal plasma P1NP concentrations predict better growth response to GH treatment during the first year in ISS children. Greater increases in its concentrations after 3-6 months of GH treatment may also predict a better growth response in both ISS and IUGR.     

Normal growth hormone secretion in growth hormone insufficient children retested after completion of linear growth

OBJECTIVE The recognition of the syndrome of adult GH deficiency suggests that young GH deficient adults, deprived of GH replacement at completion of linear growth, may suffer effects of GH deficiency. We assessed GH reserve in young adults previously diagnosed as having idiopathic GH insufficiency, who were treated with hGH replacement (14 IU/m²/week) in childhood. DESIGN Eight patients (7 males, 1 female) diagnosed as having GH insufficiency by insulin tolerance test (ITT) in childhood (ages 8.5–15.6 years) were retested by ITT at completion of linear growth (ages 15.1–19.6 years), 3 months after discontinuation of hGH therapy. MEASUREMENTS GH reserve was measured during ITT at diagnosis and at retesting. Height velocity (HV) and HV SDS were calculated before and during GH therapy. RESULTS At diagnosis, the mean peak GH response to ITT was 10.5 ± 2.0 mU/l (range 7.7–13.6). At retesting, mean GH was 52.4 ± 33.2 mU/l (range 10.4–100), 7/8 subjects having peak GH levels greater than 15 mU/l. During hGH therapy mean HV increased from 4.0 ± 1.5 cm/year at diagnosis to 7.3 ± 1.9 cm/year during the 1st year (P = 0.004) and 6.9 ± 2.3 cm/year during the 2nd year (P = 0.02). Mean HVSDS increased from ?1.6 ± 2.1 at diagnosis to 3.1 ± 2.9 during the 1st year (P = 0.004) and 2.2 ± 4.2 during the 2nd year (P = 0.05, NS) of treatment. CONCLUSIONS Seven out of 8 children diagnosed as having idiopathic GH insufficiency had normal GH secretion at completion of linear growth. Children with GH insufficiency cannot be assumed to become GH deficient adults and should not continue on GH therapy into adult life without reinvestigation. All who were GH insufficient children should be retested at completion of linear growth to identify those who are truly GH insufficient adults and may benefit from replacement therapy.     

Akt phosphorylation in lymphocytes provides an index of in vitro insulin-like growth factor I sensitivity associated with growth hormone-induced growth

CONTEXT: Because IGF-I is the main mediator of GH action on osteogenic cells, individual differences in IGF-I sensitivity are expected to contribute to the variations of GH effects on growth. In GH-treated children, the variable responses in growth rates at a specific IGF-I target level indicate heterogeneity of responses to serum IGF-I exposures. OBJECTIVES: This study tested a cell-based assay as an index of individual IGF-I sensitivity that could help dissect GH pharmacogenetics. DESIGN: Akt phosphorylation (P-Akt) was quantified in response to IGF-I in fresh lymphocytes from 50 short children (25 with idiopathic short stature and 25 born short for gestational age) whose growth parameters were being prospectively monitored during the first year of GH therapy (86 +/- 20 mug/kg.d). RESULTS: Intra-individual triplicate measurements of IGF-I-stimulated P-Akt were reasonably consistent (0.11 < or = sd; mean < or = 0.23). Among the 50 children, the distribution of P-Akt in lymphocytes stimulated by 125 ng/ml IGF-I was closely associated with the growth response to GH administration (univariate P = 0.001). Both GH dosage (P = 0.006) and the fold increase in IGF-I levels (P = 0.04) in response to GH (P = 0.04) were also correlated with the growth response. CONCLUSION: Lymphocytes are the only IGF-I target cells that can be easily studied in clinical research. IGF-I-stimulated P-Akt in these cells was found to be a predictor of GH efficacy, supporting a significant role of the first steps of IGF-I signaling in the individual variability of GH effects on growth.     

Long-term results of growth hormone therapy in children with short stature, subnormal growth rate and normal growth hormone response to secretagogues

BACKGROUND AND OBJECTIVE Growth hormone treatment In children with Idiopathic short stature (ISS) leads to growth acceleration in the first years, but the effect on final height is still poorly documented. We therefore studied the long-term effect of GH therapy in children with Idiopathic short stature. DESIGN We have treated 27 prepubertal children with ISS with recombinant human GH (rhGH) in an initial dosage of 2 IU/m² body surface/day subcutaneously, which was doubled either after the first year if the height velocity increment was less than 2 cm/year, or thereafter if height velocity fell below the P50 for bone age. Growth and bone maturation of the treatment group (ISS group, n= 21) were compared to those of an untreated control group with ISS (ISS controls, n= 27) and of a group of rhGH treated children with isolated GH deficiency (GHD group, n= 7). RESULTS In 9 patients of the ISS group still on treatment, height standard deviation score (HSDS) for chronological age increased from ?3.8±0.7 to ?2.3±0.9 (mean±standard deviation) over 6 years, while in matched ISS controls HSDS for age did not change. HSDS for age in the GHD group increased from ?3.9±0.6 to ?1.8±0.7 after 4 years, significantly more than the ISS group. Bone maturation was accelerated In the ISS and GHD groups. HSDS for bone age and predicted adult height did not change in either group. Final height in 12 children of the ISS group was ?2.6±1.0 SDS. In the untreated controls final height was similar. A low integrated GH concentration over 24 hours, a low GH peak to provocative stimuli, and minimal initial BA delay predicted a favourable outcome. CONCLUSION rhGH treatment In this group of children with Idiopathic short stature did not increase average final height. Part of the heterogeneity of the response can be attributed to the variation in endogenous GH secretion and initial bone age delay.     

Growth hormone regimens in Australia: analysis of the first 3 years of treatment for idiopathic growth hormone deficiency and idiopathic short stature

Objective To investigate response to growth hormone (GH) in the first, second and third years of treatment for all idiopathic GH‐deficient (GHD) and idiopathic short stature (ISS) patients in Australia. Context Eligibility for subsidized GH treatment in Australia is determined on auxological criteria for the indication of Short Stature and Slow Growth (SSSG), which includes ISS (SSSG‐ISS). The biochemical GHD (BGHD, peak GH < 10 mU/l) and SSSG indications are treated similarly: starting dose of 4·5 mg/m²/week with provision for incremental dosing. Some ISS patients were specifically diagnosed with familial short stature (SSSG‐FSS). Design Responses for each year of treatment for BGHD, SSSG‐ISS and SSSG‐FSS cohorts were compared in relation to influencing variables and with international benchmarks. The effect of incremental dosing was assessed. Patients Australian BGHD, SSSG‐ISS and SSSG‐FSS patients who had completed 1, 2, or 3 years of treatment and were currently receiving GH. Measurements Growth hormone dose, change in height‐standard deviation score (ΔSDS) and growth velocity (GV). Results First‐year response was 2–3 times greater than that in subsequent years: ΔSDS_{1st year} = 0·92, 0·50 and 0·46 for BGHD, SSSG‐ISS and SSSG‐FSS, respectively. Responses were similar to international reports and inversely related to age at commencement of GH. First‐year GV‐for‐age for BGHD patients was similar to international standards for idiopathic GHD. However, girls had an inferior response to boys when treatment commenced at <6 years of age. First‐year GV‐for‐age for SSSG‐ISS/FSS patients was less than ISS standards. Dose increments attenuated the first‐ to second‐year decline in response to BGHD but marginally improved the responses for SSSG‐ISS/FSS. Conclusions The Australian auxology‐based GH programme produces comparable responses to international programmes. A lower starting dose is offset by the initiation of treatment at younger ages. Incremental dosing does not appear optimal. A first‐year dose of 6·4–6·9 mg/m²/week for GHD and 8·9 mg/m²/week for ISS with early commencement of GH treatment may be most efficacious.     

Treatment of radiation-induced growth hormone deficiency with growth hormone-releasing hormone

In children with hypothalamic causes for GH deficiency there are theoretical reasons why a GHRH analogue might be better than conventional GH therapy in promoting growth. OBJECTIVEWe have aimed to determine the efficacy and safety of growth hormone-releasing hormone (GHRH) (1–29)-NH₂ given as a twice daily subcutaneous injection in the treatment of growth failure in children with radiation-induced GH deficiency. DESIGNA multicentre study comparing growth before and after 1 year of treatment with GHRH (1–29)-NH₂, 15 μg/kg twice daily, by subcutaneous injection in children with radiation-induced GH deficiency. On completion of the study year all children were treated with GH (05 U/kg/week) and growth parameters were documented over the next year. PATIENTSNine children (six boys) with radiation-induced GH deficiency following cranial (n = 4) or craniospinal (n = 5) irradiation for a brain tumour distant from the hypothalamic–pituitary axis (n = 8) or prophylaxis against central nervous system leukaemia (n = 1) were studied. All were prepubertal when the study commenced, which was at least 2 years from radiotherapy. MEASUREMENTSAnthropometry and pubertal staging were carried out at 3-monthly intervals and bone age estimations at 6-monthly intervals (TW2 method). Pretreatment standing height velocities were compared with values during the year of GHRH treatment and then after the first year of GH therapy. In those that had received craniospinal irradiation, a change in leg-length Standard deviation score (SDS) was noted before and after GHRH therapy. Changes in skin-fold thickness and bone age during the GHRH study year were documented. Adverse events and 3-monthly measurements of clinical chemistry, haematology, lipid profile and thyroid function were recorded. RESULTSThere was a significant increase in height velocity from 33 (SD 11) cm/year before treatment, to 60 (SDS 15) cm/year after 1 year of GHRH treatment (P = 0004). GHRH maintained or improved the leg length SDS in children who had received craniospinal irradiation. Bone age increased by a mean of 11 years/chronological year during treatment with GHRH. Subsequent height velocity during 1 year of GH therapy was 75 (SD 15) cm/year. No adverse changes in biochemical or hormonal analyses were noted or adverse events that could be attributed to GHRH therapy. One child went into puberty during the GHRH study year and three were pubertal during the first year of GH therapy. CONCLUSIONIn cranially irradiated children, GHRH was effective in increasing growth velocity but this was less than that seen in response to GH therapy, although it matched that in children with isolated idiopathic GH deficiency treated with the same dose and schedule of GHRH administration.     

Growth hormone treatment of short Chinese children with β-thalassaemia major without GH deficiency

OBJECTIVE Despite regular transfusion and desferoxamine treatment, growth failure Is commonly seen In adolescent children with β-thalassaemla major. The growth failure has been thought to be due to GH resistance rather than GH deficiency. We Investigated the effect of GH on short non-GH deficient children with β-thalassaemia. DESIGN Recombinant human GH was given In a dose of 0-14IU/kg/day subcutaneously in an open study. PATIENTS Fifteen prepubertal Chinese children with β-thalassaemia major (ranging from 7.16 to 14.7 years In age) with height ?1.5 SD or more below the population mean for age and a growth velocity of less than 5 cm/year were treated with growth hormone for one year. All children had peak GH response >15mlU/l to insulin Induced hypoglycaemia and normal thyroid function and adrenal reserve. MEASUREMENTS Anthropometric measurements were performed every 3 months. Morning urine was tested twice weekly for glycosuria. Blood count, renal and liver function tests, fasting blood glucose, IGF-I and fructosa-mine levels were assessed at entry and every 3 months during treatment. Fasting Insulin was measured before and after 3 and 12 months of GH treatment. Skeletal maturity was assessed before and after one year of treatment. RESULTS Treatment was stopped in two children after 6 months because of poor growth response and noncompliance with treatment and In one child at 9 months because of bone marrow transplantation. In the 13 children, the growth velocity increased from 3.6±0.7 cm/year to 8±1.2 cm/year after one year of GH treatment (P<0.001). IGF-I was low before treatment (10.1±2.7nmol/l), rising significantly to 15.8±4.8, 18.4±4.6, 19.3±6.4 and 21.9±7.5nmol/l at 3, 6, 9 and 12 months of treatment (P<0.005). The mean pretreatment bone age in the 13 children was 9.58±1.41 years and increased to 10.53±1.43 years after one year of treatment (ΔBA/CA 0.95±0.3 years). None of the patients developed glycosuria or hypertension. There was no significant change in blood count, renal and liver function, thyroid function, fasting blood glucose or insulin concentrations during treatment. CONCLUSION Growth failure In these children with normal GH reserve and low serum IGF-I concentrations would suggest GH insensltlvity. Supraphyslologlcal doses of exogenous GH can cause a significant increase In serum IGF-I levels and a significant Improvement in short-term growth of short children with β-thalassaemia major.     

Biochemical markers of growth hormone (GH) sensitivity in children with idiopathic short stature: individual capacity of IGF-I generation after high-dose GH treatment determines the growth response to GH

OBJECTIVE AND PATIENTS: To assess multiple dose-response relationships between three GH doses (1.5, 3.0 and 6.0 IU/m2) and nine different biochemical markers of GH sensitivity in a well-defined group of 17 children with idiopathic short stature (ISS). DESIGN AND MEASUREMENTS: Serum levels of IGF-I, IGF-II and IGFBP-3, and peripheral markers leptin, C-terminal propeptide of type I collagen (PICP) and N-terminal propeptide of type III collagen (PIIINP), alkaline phosphatase (AP) and osteocalcin (OC) were measured at the start and after 2 and 12 weeks of periods of no treatment, GH 1.5 IU/m2 and GH 3.0 IU/m2. Twelve-week washout periods were applied between the 12-week GH-treatment periods. High-dose GH treatment was given during the second year of study and all serum markers were measured at start, after 2 and 12 weeks and 1 year of GH 6.0 IU/m2. In 18 non-GH-treated children with ISS the same parameters were measured yearly. The bone resorption marker urinary deoxypyridinoline (DPD) was measured during 12-h day and night periods at start and after 2 weeks GH 1.5, 3.0 and 6.0 IU/m2. RESULTS: All markers were GH dependent, but the timing of maximal response varied among different markers. Height SDS at start, age at start and IGF-II at baseline were inversely related to the first-year growth response (r = -0.73, P = 0.001; r = -0.53, P = 0.03; and r = -0.53, P = 0.03, respectively). Some statistically significant correlations between biochemical responses on low GH doses (1.5 or 3.0 IU/m2) and second-year growth response were found, but these showed no consistent pattern. However, all changes in IGF-I SDS after GH 6.0 IU/m2 measured either after 2 or 12 weeks or 1 year correlated significantly with the second-year growth response (r = 0.55, P = 0.02; r = 0.81, P = 0.001; and r = 0.86, P < 0.001, respectively). Baseline or GH-stimulated levels of peripheral markers did not correlate with the growth response. CONCLUSION: The individual capacity of IGF-I generation after high-dose GH treatment (6.0 IU/m2) determines the growth response on high-dose GH treatment. Peripheral markers do not seem to play a role in growth prediction of children with ISS.     

The effect of growth hormone replacement therapy in hypopituitary adults on calcium and bone metabolism*

OBJECTIVE The importance of growth hormone (GH) for normal skeletal growth in childhood and adolescence is well established but much less is known about its action on the adult skeleton. We therefore wished to investigate the effects of replacement treatment with blosynthetic human GH in hypopituitary adults on aspects of calcium homeostatis, bone metabolism and bone mineral mass. PATIENTS Forty hypopituitary adults (21 females and 19 males; aged 19–67 years). DESIGN A prospective randomized double-blind placebo-controlled trial lasting for 6 months. PROTOCOL Following baseline assessments, GH was given in a daily dose of 0·02–0·05 IU/kg body weight subcutaneously (or a placebo (P)) at bedtime. Patients were reviewed at 1, 3 and 6 months. MEASUREMENTS Plasma calcium, phosphate and total plasma alkaline phosphatase were measured at 0, 1, 3 and 6 months. Serum insulin like growth factor I (IGF-I), osteocalcin, procollagen 1 carboxyterminal peptide (P1CP) and intact parathyroid hormone (PTH) level, 24-hour urinary calcium and creatinine excretion were all measured at 0 and 6 months. Bone mineral density of total body and lumbar spine was also measured by dual energy X-ray absorptiometry at 0 and 6 months in 12 patients on GH and 14 on placebo. RESULTS Thirty-eight patients completed the study (18 on GH, 20 on placebo). Serum IGF-I Increased significantly on GH treatment (mean ± SD) (GH: 276 ± 197 vs P: 88 ± 50 μg/l, P < 0 0001 at 6 months). Plasma calcium increased slightly but significantly in the GH-treated group (2·23 ± 0·11–2·29 ± 0·11 mmol/l, P<0·05). At the end of the study, plasma calcium was however similar on GH and placebo (GH, 2·29 ± 0·11; P, 2·26 ± 0·09 mmol/l). Plasma phosphate increased on GH (GH: 1·02±0·23–1·32±0·19; P: 0·99±0·16–0·96±0·12 mmol/l over the 6 months of treatment, P<0·001). There was no significant change in the urinary calcium excretion on GH therapy. Plasma total alkaline phosphatase, osteocalcin and P1CP were significantly higher on GH than P at 6 months (alkaline phosphatase: GH: 104±32 vs P: 69±32 U/I, P<0·01, osteocalcin: GH: 17·2±8·0 vs P: 5·3±3·2 μg/l, P<0·001 and P1CP: GH: 207 ± 152 vs P: 93±31 μg/l, P<0·01). There was no difference in the intact parathyroid hormone level (GH: 31 ± 14 vs P:31 ± 15 ng/l, NS). No significant change was observed in bone mass after 6 months of GH treatment, either in total body bone mineral content or in the lumbar spine. CONCLUSION In this large study, GH replacement in hypopituitary adults for 6 months increased bone turnover but did not affect bone mineral content. Longer-term studies are required to assess further any effect on bone mass.     

重组人生长激素治疗单纯性生长激素缺乏症和特发性矮小症患儿血清C型利钠肽氨基末端浓度与生长速率的变化

目的 探讨单纯性生长激素缺乏症(isolated growth hormone deficiency,IGHD)以及特发性矮小症(idiopathic short stature,ISS)患儿经重组人生长激素(recombinant human growth hormone,rhGH)治疗后,血清C型利钠肽氨基末端(NTproCNP)浓度的变化及其与生长速率(growth velocity,GV)的关系.方法 共有48例青春期前的患儿纳入研究(IGHD 25例,ISS 23例),并给予rhGH治疗1年.治疗前及治疗后6个月分别测血清胰岛素样生长因子-Ⅰ (IGF-Ⅰ)和NTproCNP的浓度.治疗1年后,计算所有患儿的GV、身高Z积分(HTSDS)以及身高Z积分的变化值(△HTSDS).结果 IGHD组中,治疗前后IGF-I Z积分的变化值(△IGF-ISDS)、NTproCNP浓度的变化值(△NTproCNP)与治疗1年中GV呈正相关(r=0.407,P=0.044;r=0.490,P=0.013);治疗前生长激素(CH)峰值也与治疗前IGF-ISDS、NTproCNP浓度(r=0.558,P=0.004;r=0.630,P=0.001)以及治疗后△IGF-ISDS与△NTproCNP呈正相关(r=0.466,P=0.019).而在ISS患儿中,治疗1年中GV只与治疗后△NTproCNP相关(r=0.845,P＜0.01).结论 在IGHD和ISS患儿应用rhGH的促生长治疗中,NTproCNP水平随着生长速率的增加而增加.因此除了IGF-I,NTproCNP作为一种新的生化标记物,也可用于评估和预测这两类患儿在rhGH治疗后的GV变化.     

The effects of recombinant human insulin-like growth factor I on growth hormone secretion in adolescents with insulin dependent diabetes mellitus

OBJECTIVE It has been proposed that low IGF-I levels and reduced IGF-I bioactivity may lead to elevated GH levels in adolescents with insulin dependent diabetes (IDDM). We have therefore studied the effects of human recombinant insulin-like growth factor I (rhIGF-I) administration on GH levels and GH secretion in adolescents with IDDM. PATIENTS Nine late pubertal adolescents (four male and five female) with IDDM. DESIGN A double-blind placebo controlled study of rhIGF-I administered subcutaneously in a dose of 40 μg/kg body weight at 1800 h. MEASUREMENTS IGF-I and GH concentrations were measured at regular intervals throughout the study. Twenty-two hour GH secretory rates were calculated by deconvolution analysis. Overnight GH profiles were analysed by distribution analysis, and Fourier transformations were performed on both overnight GH concentrations and GH secretory rates. RESULTS Mean IGF-I levels over the 22-hour study period were significantly elevated following rhIGF-I administration (350 ± 26 vs 205 ± 21 μg/l (mean ± SEM), P<0 001). Mean 22-hour GH levels were reduced following rhIGF-I administration (19.4 ± 4.0 compared with 33.6 ± 5.8 mU/l; P= 001). Distribution analysis demonstrated that the reduction in GH levels was due to changes in the proportion of values at both high and low concentrations. Deconvolution analysis also revealed a significant overall reduction in GH secretory rate following IGF-I administration (1.81 ± 0.30 vs 2.98 ± 0.47 mU/min, P= 0.01) which was still apparent during the final 5.5 hours of the study period (1.51 ± 0.30 vs 2.76 ± 0.61 mU/min, P= 002). The dominant periodicity of GH secretory episodes as determined by Fourier transformation was between 120 and 180 minutes after both IGF-I and placebo. CONCLUSIONS In late pubertal adolescents with IDDM the rise in IGF-I levels following rhIGF-l administration in a subcutaneous dose of 40 μg/kg body weight leads to a significant reduction in GH levels and GH secretory rate. The reduction in GH secretion is due to changes in pulse amplitude rather than frequency. A reduction in GH secretion was apparent at the beginning and also towards the end of the 22-hour study period.     

Chronic pulsatile infusion of growth hormone to growth-restricted fetal sheep increases circulating fetal insulin-like growth factor-I levels but not fetal growth

Intra-uterine growth restriction (IUGR) is a major cause of perinatal mortality and morbidity. Postnatally, growth hormone (GH) increases growth, increases circulating insulin-like growth factor (IGF)-I levels, and alters metabolism. Our aim was to determine if GH infusion to IUGR fetal sheep would alter fetal growth and metabolism, and thus provide a potential intra-uterine treatment for the IUGR fetus. We studied three groups of fetuses: control, IUGR+ vehicle and IUGR+GH (n=5 all groups). IUGR was induced by repeated embolisation of the placental vascular bed between 110 and 116 days of gestation (term=145 days). GH (3.5 mg/kg/day) or vehicle was infused in a pulsatile manner from 117 to 127 days of gestation. Embolisation reduced fetal growth rate by 25% (P<0.01) and reduced the weight of the fetal liver (20%), kidney (23%) and thymus (31%; all P<0.05). GH treatment further reduced the weight of the fetal kidneys (32%) and small intestine (35%; both P<0.04), but restored the relative weight of the fetal thymus and liver (P<0.05). Embolisation decreased fetal plasma IGF-I concentrations (48%, P<0.001) and increased IGF binding protein 1 (IGFBP-1) concentrations (737%, P<0.002). GH treatment restored fetal plasma IGF-I concentrations to control levels, while levels in IUGR+vehicle fetuses stayed low (P<0.05 vs control). IGFBP-1 and IGFBP-2 concentrations were about sevenfold lower in amniotic fluid than in fetal plasma, but amniotic and plasma concentrations were closely correlated (r=0.75, P<0.0001 and r=0.55 P<0.0001 respectively). Embolisation transiently decreased fetal blood oxygen content (40%, P<0.002), and increased blood lactate concentrations (213%, P<0.04). Both returned to pre-embolisation levels after embolisation stopped, but blood glucose concentrations declined steadily in IUGR+vehicle fetuses. GH treatment maintained fetal blood glucose concentrations at control levels. Our study shows that GH infusion to the IUGR fetal sheep restores fetal IGF-I levels but does not improve fetal growth, and further reduces the fetal kidney and intestine weights. Thus, fetal GH therapy does not seem a promising treatment stratagem for the IUGR fetus.     

GH responsiveness in a large multinational cohort of SGA children with short stature (NESTEGG) is related to the exon 3 GHR polymorphism

OBJECTIVE: The polymorphic deletion of exon 3 of the GH receptor (d3-GHR) has recently been linked to the magnitude of growth response to recombinant human GH (rhGH) therapy in short children with or without GH deficiency. We investigated this association in a large multinational cohort from the Network of European Studies of Genes in Growth (NESTEGG), comprising short children born small for gestational age (SGA). DESIGN: The study included short prepubertal SGA children treated with rhGH for 1 or 2 years. POPULATION: Two hundred and forty white Caucasian SGA children (138 male, 102 female) aged 6.6 +/- 2.3 years with a height at -3.0 +/- 0.7 SDS at start of rhGH treatment; 193 ethnically matched controls. METHODS: The GHR polymorphism (fl/fl, fl/d3 or d3/d3) was genotyped by polymerase chain reaction (PCR) multiplex assay. Growth velocity (G/V) in cm/year and changes in GV during the first and second year of rhGH treatment were evaluated. RESULTS: The change in GV was significantly greater in SGA children carrying one or two copies of the d3-GHR allele (P = 0.038 for the first year and P = 0.041 for the second year of GH treatment), but the change in height was not significantly different. Birthweight was significantly lower in SGA children with the d3/d3 genotype than in SGA children with the fl/fl genotype (P = 0.034) and in those with the fl/d3 genotype (P = 0.016). CONCLUSION: Our data, based on a large cohort, showed that the exon 3 GHR polymorphism is associated with responsiveness to rhGH treatment in SGA children with short stature.     

Protein intake during aggressive calorie restriction in obesity determines growth hormone response to growth hormone-releasing hormone after weight loss

OBJECTIVE We evaluated the influence of two types of calorie restriction, total fast or very low calorie diet, on GH responsiveness to GHRH in severely obese patients. DESIGN Twenty patients with massive obesity underwent one of two types of calorie restriction, total fast (10 patients) or very low calorie diet (10 patients). MEASUREMENTS Fasting GH, IGF-I, glucose, insulin and GH secretion after GHRH (100 ug i.v.) were assessed in all patients before and after diet therapy. RESULTS Both types of diet produced similar weight reduction (total fast, 5.6 ± 1.6 kg/m²vs very low calorie diet, 5.6 ± 1.5 kg/m² mean ± SD). A significant increase in the integrated GH secretion was observed after weight-loss with very low calorie diet (17 ± 9 vs27 ± 12mU/l min; P < 0.05). However, no change was found in GH response after weight loss with total fast (13 ± 5 vs 15 ± 7 μ/l min). Glucose, insulin and IGF-I levels showed a significant decrease with weight reduction which was similar for both groups. CONCLUSION These findings suggest that the type of dietary manipulation during calorie restriction in obese patients may influence the changes in GH response to GHRH after weight loss.     

Effect of growth hormone replacement on bone mass in adults with adult onset growth hormone deficiency

OBJECTIVE Previous studies of the effect of GH replacement on bone mass in adults with GH deficiency have produced conflicting results. We have studied the effect of 6 and 12 months of GH replacement on bone mass in adults with adult onset GH deficiency. DESIGN Double blind placebo controlled study of GH replacement (0.125 IU/kg/week for the first month and 0.25 IU/kg/week thereafter) for 6 months and an open study for a further 6 or 12 months. PATIENTS Twenty-two adults (10 men, 12 women), aged 41.5±2.1 years (mean ± SE, range 23.6–59.5), with adult onset GH deficiency. MEASUREMENTS Single-energy quantitative computed tomography was used to measure vertebral trabecular bone mineral density (BMD), single-photon absorptiometry (SPA) was used to measure forearm cortical and integral bone mineral content and BMD and dual-energy X-ray absorptiometry (DXA) was used to measure lumbar spine, femoral neck, trochanteric and Ward's triangle Integral BMD. RESULTS After 6 months of GH replacement (n=21) there was a significant decrease In forearm cortical BMD (SPA: median change ?0.009g/cm², P=0.01), forearm Integral BMD (SPA: median change ?0.016g/cm², P=0.03), lumbar spine BMD (DXA: median change ?0.022g/cm²; P=0.003) and femoral neck BMD (DXA: median change ?0.029g/cm², P=0.006). After 12 months of GH replacement (n=13) there was a significant decrease in lumbar spine BMD (DXA: median change ?0.035 g/cm², P=0.002) from baseline. There was no significant Increase in bone mass at any site after 6 or 12 months of GH replacement. Change In bone mass was not influenced by sex of the patient or by presence or absence of additional pituitary hormone deficiencies. CONCLUSION The response of bone mass to 6 and 12 months of GH replacement in adults with adult onset GH deficiency is disappointing. Longer-term studies are required to determine whether prolonged GH replacement has a beneficial effect on bone mass.     

Whole body and regional soft tissue changes in growth hormone deficient adults after one year of growth hormone treatment: a double-blind, randomized, placebo-controlled study

OBJECTIVE Adults with GH deficiency (GHD) exhibit changes in body composition. Studies of the effects of GH substitution on body composition have been short-term or not adequately controlled. The purpose of this study was to evaluate the long-term effects of GH on soft tissue using dual-energy X-ray absorptlometry (DEXA). This technique enables assessment of whole body as well as regional soft tissue composition. DESIGN A double-blind, randomized, placebo-controlled study in patients with acquired GHD. The therapeutic regime consisted of biosynthetic human GH (2.0 lU/m² per day) or placebo, given as a daily subcutaneous injection at 2000 h for 12 months. PATIENTS Twenty-nine patients with acquired GHD (GH < 10 μg/l (< 20 mU/I) following standard provocative tests) in whom additional hormone replacement was maintained. MEASUREMENTS Soft tissue determinations by DEXA scan, height, weight, foot volume and finger clrcumference were recorded together with serum IGF-I at baseline and after 12 months. RESULTS Twelve months of GH therapy induced a total fat mass (FM) reduction of (mean ± SEM) 4.88 ± 0.58 kg (P < 0–002) (n= 13) corresponding to 21.5% of the total FM. The reduction in fat was most marked in the trunk, i.e. 3.07 ± 0.29 kg (P < 0–002) corresponding to 61% of the total FM reduction. Total lean soft tissue mass (LSTM) increased by 3.31 ± 0.81 kg (P < 0.001). Regional changes for arm and leg in the GH group amounted to 0.32 ± 0.08 kg (P < 0002) and 0.71 ± 0.14 kg (P < 0.002), respectively, without accompanying significant changes in truncal LSTM between the groups. The foot volume was Increased by 55.8 ± 15.7 ml (P < 0007) and the finger circumference by 2.67 ± 0.5 mm (P < 0005) on active treatment with no significant changes in the placebo group. CONCLUSIONS Twelve months of GH therapy induced marked changes in soft tissue; fat mass was reduced, particularly in the trunk (61 % of total fat mass reduction) whereas lean soft tissue mass increased more in the extremities. The data imply that GH-induced changes in body composition are maintained with long-term therapy.     

Treatment with GHRH(1-29)NH2 in children with idiopathic short stature induces a sustained increase in growth velocity

OBJECTIVE Therapy with GHRH in patients with mild GH insufficiency appears to be more effective than in those with severe insufficiency. We, therefore, studied the clinical response of children with idiopathic short stature to treatment with GHRH(1-29)NH₂ (GHRHa) for a period of 12 months. DESIGN Eighteen short pre-pubertal children (aged 4·3-11·0 years, 17 male) with idiopathic short stature (height < 3rd centile, peak GH to provocative testing > 20 mu/l) were recruited to receive GHRHa 20 μg/kg by twice daily s.c. injection for one year. One patient was non-compliant and was withdrawn prior to 3 months of therapy. Pretreatment height velocity was calculated for 12 months and subjects were measured 3-monthly during therapy. Overnight GH profiles and s.c. GHRH tests (20 μg/kg) were performed at 0, 3, 6 and 12 months of therapy. In addition, an i.v. GHRH test (1 μg/kg) was performed at the start and after 1 month of therapy. MEASUREMENTS Overnight GH profiles were analysed using the Pulsar program. RESULTS Mean (SD) height veloclty (HV) increased from 4·8(0·9)cm/year pre-treatment to 7·2 (1·6)cm/year after 12 months of therapy (P= 0·001). The children growing slowly (HV < 25th centile) before treatment had a greater growth response than those growing normally (HV ≥25th centile) before treatment. Final height prediction increased by a mean (SD) of 3·4(2.6)cm. Overnight GH levels and GH responses to GHRH testing fell during the 12 months of therapy. Fasting blood glucose and insulin levels increased during therapy, as did IGF-I. Cessation of GHRHa was followed by catch-down growth during the first 3 months off therapy: mean (SD) HV 3·89(1·82)cm/year (P < 0·44), although the HV after 6 months (4·9(1·0)cm/year) and 12 months (4·4(1·0)cm/year) was not different from pretreatment values. CONCLUSIONS Short-term therapy with twice-daily s.c. injection of GHRHa (20 μg/kg) promoted linear growth in short children who were not GH-insufficient. The improved height velocity was sustained throughout the 12 months of treatment, followed by catch-down growth, and returned to pretreatment velocity after cessation of therapy.     

IGFs and binding proteins in short children with intrauterine growth retardation.

The aim of this study was to examine the relationship between the IGF-IGF binding protein (IGFBP) axis and insulin secretion in short intrauterine growth retardation (IUGR) children. Fifteen IUGR and 12 normal short prepubertal subjects had a 90-min frequently sampled iv glucose tolerance test performed to measure plasma glucose, insulin, IGF-I, IGF-II, IGFBP-3, and IGFBP-1. In addition, 29 nonobese prepubertal subjects of normal height had fasting plasma IGF-I and IGFBP-3 levels measured. In comparison to short normal subjects, IUGR subjects had higher plasma values for IGF-I (42 +/- 10 vs. 77 +/- 31 microg/liter; P < 0.0001), IGF-II (291 +/- 76 vs. 370 +/- 66 microg/liter; P < 0.008), IGFBP-3 (1.66 +/- 0.28 vs. 2.07 +/- 0.48 mg/liter; P < 0.0005), fasting insulin (2 +/- 1 vs. 4 +/- 2 mU/liter; P < 0.004), and acute insulin response (AIR; 215 +/- 36 vs. 504 +/- 90 mU/liter; P = 0.008). Nonobese subjects of normal height had higher plasma IGF-I (117 +/- 9 microg/liter; P < 0.0001) and IGFBP-3 (2.34 +/- 0.12 mg/liter) values than the IUGR group (P < 0.0005). During the frequently sampled iv glucose tolerance test, the magnitude of the AIR in short normal subjects was related to the fall in IGFBP-1 levels (P = 0.03); however, no relationship was seen between AIR and fall in IGFBP-1 in IUGR subjects (P = 0.24). In conclusion, short IUGR children have higher plasma IGF-I, IGF-II, and IGFBP-3, when compared with normal children matched for height, weight, and pubertal status. We speculate that hyperinsulinism secondary to insulin resistance may have led to these changes to the IGF-IGFBP axis in the IUGR group.     

Metabolic effects of growth hormone administered subcutaneously once or twice daily to growth hormone deficient adults

OBJECTIVE The aim of this study was to compare the metabolic effects of GH administered subcutaneously either once or twice daily. The actions of GH might depend upon a pulsatlle pattern of serum GH. Pulsatile and continuous intravenous delivery of GH, however, induce similar short-term metabolic effects in GH deficient patients. An improved growth response is obtained in GH deficient children when a fixed weekly GH dose Is administered by dally subcutaneous injections instead of twice or thrice-weekly intramuscular injections. A more pulsatile pattern and serum GH levels above zero might be achieved by further increasing the Injection frequency. Increased daytime GH levels might, however, adversely affect the circadian patterns of metabolic indices, whlch have been demonstrated to be more successfully reproduced by evening compared with morning GH administration. DESIGN AND MEASUREMENTS In a cross-over study, 8 GH deficient patients (age 16–43 years) were treated with 3IU/m²/24h of human GH. The dose was injected in the evening for 4 weeks and for another 4 weeks two-thirds was injected in the evening and one-third in the morning. At the end of each period the patients were admitted to the hospital for 37 hours. Steady-state profiles of GH, IGF-I, IGF binding proteins 1 and 3, Insulin, glucose, lipid Intermediates and metabolites were obtained following administration of 3IU/m² of GH (at 1900 h (one injection) and at 1900 and 0800 h (two injections). RESULTS Similar mean integrated levels of serum GH (mUII) were obtained (7·46 ± 0·84 (one injection) vs 6·46 ±0·62 (two Injections) (P = 0·15). Mean levels ± SEM of serum IGF-I (μg/I) were significantly increased (P < 0·01) following two daily GH Injections (330·3±48·1 (one Injection) vs 399·1±53·0 (two injections). Serum IGFBP-3 levels were not signlflcantly different on the two occasions, while levels of the GH Independent IGFBP-1 (μg/l) were slightly but significantly lower following twice-dally GH injections (1·61±0·42 vs 1·13 ±0·56, respectively (P < 0·04). The pattern of IGFBP-1 was opposite to that of insulin. Similar levels of insulin and glucose were obtained with both GH regimens, while levels of non-esterlfied fatty acids were significantly higher following once-dally GH injection (P < 0·001). CONCLUSIONS Twice-dally GH injections, apart from producing a more physiological serum GH profile, were superior to one Injection in increasing serum IGF-I and decreasing IGFBP-1 levels. Both of these changes tend to amplify the effects of the administered GH. Twice-daily Injections, however, resulted Ln lower night-time levels of lipid Intermediates.     

Gender difference in the response of growth hormone (GH)-deficient adults to GH therapy

While individual hypopituitary patients undoubtedly benefit from growth hormone (GH) therapy, there is considerable variability in the response to treatment. Given the expense, possible lack of benefit, and potential risks associated with long-term therapy, we sought to identify characteristics potentially associated with a favorable response to GH replacement. Twelve GH-deficient adults (seven men and five women aged 35.4+/-2.5 years, mean +/- SEM) participated in a 12-month open study of GH replacement (0.125 IU/kg/wk for 4 weeks and 0.25 IU/kg/wk thereafter) designed to examine the impact of GH on body composition, lipid profile, and psychological well-being. Using bioelectrical impedance analysis (BIA), there was a reduction in body fat (BF) and an increase in lean body mass (LBM) and total body water (TBW) (P < .05) following 12 months of GH treatment. In addition, there was a significant improvement in psychological well-being as indicated by a decrease in the Nottingham Health Profile (NHP) score (P < .05) and a decrease in both total cholesterol (P = .005) and low-density lipoprotein (LDL) cholesterol (P < .03). GH therapy was associated with an increase in fasting plasma glucose (P = .008) and hemoglobin A1c (HbA1c (P = .06). When analyzed by gender, the beneficial effect of GH was greater in men versus women for the increment in insulin-like growth factor-1 ([IGF-1] 375+/-59 v 148+/-73 microg/L, mean +/- SEM), increase in LBM (6.8+/-2.5 v -0.06+/-1.6 kg), reduction in BF (5.6+/-1.6 v 1.0+/-1.9 kg), and increase in TBW (5.0+/-1.6 v 0.14+/-1.29 L) (P < .05). HbA1c increased significantly in women (P < .05). The beneficial effect of GH tended to be greatest in those with the most significant abnormality in baseline values (P < .05). The duration of hypopituitarism showed an indirect correlation with the change in total cholesterol (P < .005). Baseline IGF-1 levels correlated directly with changes in TBW (P < .05). These data indicate that men with GH deficiency appear more responsive to GH therapy than women with respect to the increase in IGF-1 levels and improvement in body composition. In general, patients with the most significant abnormality in baseline values, the highest IGF-1 levels, and the shortest duration of hypopituitarism respond best. With long-term GH therapy, careful monitoring of glucose tolerance is indicated.