Predictors of growth response to growth hormone in otherwise normal short children.

Sixty prepubertal short children (39 boys) with heights less than 2 SD for age and gender were treated daily for 1 year with recombinant human growth hormone (GH), either 0.1 IU/kg (group 0.1, n = 32) or 0.05 IU/kg (group 0.05, n = 28). Reserve of GH was determined by at least one GH provocative stimulus and 24-hour continuous blood withdrawal to determine the integrated concentration of GH (IC-GH). All participants had a GH response to provocative tests greater than 10 micrograms/L. The height velocity (mean +/- SD) of the group as a whole increased from 4.46 +/- 1.02 to 7.59 +/- 1.65 cm/yr (p less than 0.001). The growth velocity of group 0.1 was significantly greater than that of group 0.05 (8.1 +/- 1.5 vs 7.0 +/- 1.65 cm/yr; p less than 0.01). Bone age did not advance more than 1 year during the treatment period. Growth velocity after 1 year of GH therapy was inversely correlated with the IC-GH in both groups, as was the pretreatment height velocity. We found no correlation of growth velocity during GH therapy with other measures such as parental heights, bone age/chronologic age ratio, maximal GH response to provocative tests, chronologic age, or pretreatment insulin-like growth factor I levels. We conclude that the best predictors for the 1-year growth outcome of short children with a normal GH response to provocative tests are the pretreatment growth velocity and the IC-GH. The short-term benefit from GH therapy in children with a normal growth velocity and a normal IC-GH is poor, whereas marked growth acceleration is noted in children with a low growth velocity and a low 24-hour IC-GH.     

Results of early reevaluation of growth hormone secretion in short children with apparent growth hormone deficiency

OBJECTIVE: To test the hypothesis that normalization of the growth hormone (GH) response to stimulation in patients with GH deficiency (GHD) and normal magnetic resonance imaging (MRI) of the hypothalamic-pituitary area might occur earlier than at attainment of final height. STUDY DESIGN: Prepubertal children with short stature (21 boys and 12 girls; age, 5.2-10 years), in whom a diagnosis of GHD was based on a GH response <10 microg/L after 2 pharmacologic tests (clonidine, arginine, or insulin hypoglycemia), and normal MRI of the hypothalamic-pituitary area were studied. After 1 to 6 months, all children underwent reevaluation of GH secretion by means of one of the provocative tests previously used. During that time, none of the children received GH therapy or entered puberty. RESULTS: A GH response > or =10 microg/L after retesting was found in 28 patients, and a GH response <10 microg/L was found in 5. In 9 patients, the peak GH response at diagnosis was <7 microg/L to both tests used. In 8, the GH response at retesting was > or =10 microg/L and was 9.0 microg/L in the remaining child. CONCLUSIONS: We suggest that patients with pathologic GH responses to provocative tests but normal MRI should be reevaluated and followed up before a diagnosis of GHD is firmly established.     

Evaluation of growth hormone release and human growth hormone treatment in children with cranial irradiation-associated short stature

We studied nine children who had received cranial irradiation for various malignancies and subsequently experienced decreased growth velocity. Their response to standard growth hormone stimulation and release tests were compared with that in seven children with classic GH deficiency and in 24 short normal control subjects. With arginine and L-dopa stimulation, six of nine patients who received radiation had a normal GH response (greater than 7 ng/ml), whereas by design none of the GH deficient and all of the normal children had a positive response. Only two of nine patients had a normal response to insulin hypoglycemia, with no significant differences in the mean maximal response of the radiation and the GH-deficient groups. Pulsatile secretion was not significantly different in the radiation and GH-deficient groups, but was different in the radiation and normal groups. All subjects in the GH-deficient and radiation groups were given human growth hormone for 1 year. Growth velocity increased in all, with no significant difference in the response of the two groups when comparing the z scores for growth velocity of each subject's bone age. We recommend a 6-month trial of hGH in children who have had cranial radiation and are in prolonged remission with a decreased growth velocity, as there is no completely reliable combination of GH stimulation or release tests to determine their response.     

Physiological assessment of growth hormone secretion in the diagnosis of children with short stature

Many advances characterize the research into the diagnosis of short stature in children. Increasing evidence shows a continuous spectrum of growth hormone (GH) output among GH-deficient patients and short normal children. Although biosynthetic human GH could theoretically offer the chance of treating most slowly growing children, it is not certain that all short normal children with a poor height velocity could benefit from therapy. Indeed, besides auxological findings, the assessment of GH secretion remains essential in selecting candidates for therapy. In this respect the evaluation of GH secretion by means of tests that can explore the physiological pathways involved in the hormone output appears important. Moreover some clinical evidence suggests that pharmacological stimuli cause the pituitary release of stored GH perhaps unavailable in physiological conditions. Among the classical physiological tests, the exercise test, the standardization of which has been debated, is commonly used in clinical practice. The sleep test, i.e. the evaluation of sleep-associated GH secretion, is the most important. It has no side effects and does not require the administration of exogenous stimuli. Several studies have demonstrated its reliability in diagnosing growth disorders in childhood, mainly if performed with EEG monitoring. Among the new physiological diagnostic approaches the most reliable test is the evaluation of 24-hour GH secretion. Knowledge of the integrated hormone concentrations appears particularly important in studying children who may have more subtle disturbances in GH secretion. These cases show normal GH response to provocative stimuli but show a reduced hormone output over 24 h. Indeed they respond well to human GH treatment.     

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目的探讨血清生长激素(GH)、胰岛素样生长因子-1(IGF-1)及尿GH检测对矮小儿童诊断的意义。方法华中科技大学同济医院儿科于2004-11—2005-06对106例矮小儿童进行垂体功能复合刺激试验,试验前收集所有受试者夜间12h(2000~800)尿。另选取19例正常青春发育期前儿童为对照组。对垂体功能复合刺激试验GH分泌异常的56例矮小儿童,用ELISA方法检测相应的血清GH、IGF-1及尿中GH水平,并进行相关分析。结果根据垂体功能复合刺激试验的GH检测结果将矮小儿分类,包括完全性GH缺乏症(cGHD)25例、部分性GH缺乏症(pGHD)9例和GH神经分泌功能障碍(GHND)22例。GHD组患儿血清IGF-1、尿GH水平与正常儿相比明显降低(P<0·01)。pGHD和GHND组患儿血IGF-1水平波动较大,无统计学差异。GHND组患儿尿GH水平按ng/g肌酐(Cr)计量显著低于正常对照相(P<0·05),而按ng/12h尿量计算值虽低于正常组,但无统计学意义(P>0·05)。pGHD组患儿尿GH水平按两种方法计量值均介于正常和GHD患者之间,与正常及GHD患者比较均有显著性差异(P均<0·05)。cGHD和pGHD组患儿尿GH的ng/gCr计量值与其血GH峰值呈显著性正相关(rcGHD=0·556,P<0·05;rpGHD=0·423,P<0·05),GHND组患儿尿GH的ng/gCr计量值与其血中GH峰值无相关性(P>0·05)。结论尿GH水平测定无创、简便,配合IGF-1等指标的检测,对于矮小儿童的诊断和鉴别诊断具有重要意义。     

Circulating immunoreactive growth hormone releasing hormone concentrations and growth hormone response to growth hormone releasing hormone in short children

To study the role of peripheral immunoreactive growth hormone releasing hormone (ir-GHRH) concentrations and the GHRH test in the evaluation of growth hormone (GH) secretion in short stature, 46 children with a mean age of 9.4 years (range 1.6–16.3 years) and a mean relative height score of –3.2 SD (range –5.0–2.1 SD) were investigated. The children were divided into prepubertal (n=35) and pubertal (n=11) and the prepubertal children further into three groups based on their maximal GH responses to insulin-induced hypoglycaemia (IIH) and clonidine: (1) GH deficient subjects (maximal GH<10 g/l in both test); (2) discordant responders (maximal GH<10 g/l in one test and 10 g/l in the other); and (3) normal responders (maximal GH10 g/l in both test). Peripheral ir-GHRH concentrations were measured during the IIH test by radioimmunoassay after purification of plasma samples on Sep-pak cartridges. Among the prepubertal children 10 fell into group 1, 16 into group 2 and 9 into group 3. Children in group 1 were older, than those in group 3. There were no significant differences in relative heights and weights or absolute and relative growth velocities between the groups. Subjects in groups 1 and 2 had lower maximal GH responses to GHRH than those in group 3. There were no significant differences in the basal plasma ir-GHRH concentrations between the groups. Nine children (19.6%) had somatotrophs with a poor response to a single dose of exogenous GHRH (maximal GH<10 g/l). These subjects had increased basal plasma ir-GHRH concentrations. All of them had a decreased GH response to IIH and/or clonidine. Pubertal children had higher circulating ir-GHRH levels than the prepubertal subjects. There was an inverse correlation (r=–0.46;P<0.001) between the maximal GH response to GHRH and calendar age in the whole series. These observations suggest that: (1) a substantial proportion of short children have a heterogenous GH response to pharmacological stimuli necessitating complementary evaluation of their spontaneous GH secretion; (2) a poor response to exogenous GHRH is associated with increased ir-GHRH levels in the peripheral circulation; (3) all children with normal GH responses in pharmacological tests respond normally to GHRH and (4) the pituitary sensitivity to GHRH decreases with increasing age. Peripheral ir-GHRH concentrations do not differentiate between short children with growth hormone deficiency (GHD) and those with undefined short stature. The GHRH test is of limited value in the diagnosis of GHD, since a normal GH response does not exclude GHD, although a subnormal response appears to reflect dysfunctional GH secretion.     

Noonan's syndrome: abnormalities of the growth hormone/IGF-I axis and the response to treatment with human biosynthetic growth hormone

Auxological and endocrine data from 6 children (3 male, 3 female) aged 8.5-12.8 years with Noonan's syndrome and the results of treatment with human biosynthetic growth hormone (hGH) are presented. All the children were short (Ht SDS -3.5 to -2.3) and height velocity SDS ranged between -1.76 and +0.03. The maximum plasma growth hormone (GH) response to standard provocation tests ranged from 17 to 52 mU/l, yet, plasma insulin-like growth factor I (IGF-I) concentrations were low or low normal. Overnight GH secretory profiles were normal in all but 2 children who had disordered pulsatility with high trough concentrations. In 5 children who have completed one year of hGH therapy mean height velocity increased from 4.8 to 7.4 cm/year and the height velocity SDS ranged from +0.2 to +3.75. This improvement was associated with an increase in plasma IGF-I in three subjects. These results suggest that a defect of the GH/IGF-I axis may be present in some children with Noonan's syndrome and hGH therapy may have a role in the management of the short stature in these children.     

A controlled trial of methionyl growth hormone therapy in prepubertal children with short stature, subnormal growth rate and normal growth hormone response to secretagogues. Dutch Growth Hormone Working Group

Thirty short and slowly growing children with normal plasma growth hormone (GH) responses to standard provocation tests were randomly assigned to either a group (n = 20) undergoing treatment with methionyl GH (somatrem), 2 IU per m2 body surface s.c. daily, or a control group (n = 10). Twelve out of 18 children who completed the first year of treatment showed a height velocity increment of more than 2 cm/year. The mean (SD) growth velocity of the treatment group increased by 3.0 (1.9) cm/year over the first year, compared with -0.2 (0.7) cm/year in the control group. Neither parameters of endogenous GH secretion nor plasma IGF-I levels showed a significant correlation with the growth response. Of the auxological variables studied, pre-treatment growth velocity (r = -0.8) and the short-term height velocity increment (r = 0.7-0.9) showed significant correlations with the growth response in the first year of treatment. Somatrem therapy was without side effects, except in one child who developed anti-GH antibodies in combination with a poor growth response.     

Evaluation of growth hormone secretion after completion of therapy

BACKGROUND: Growth hormone (GH) reserve in young adults previously diagnosed as having GH insufficiency, who were treated with human (h)GH replacement in childhood needs confirmation in adulthood. METHODS: Nine patients (seven males, two females; two empty cella, one hypoplasia of the hypophysis and six with idiopathic GH deficiency) diagnosed as having GH insufficiency by the insulin tolerance test (ITT) and dopamine stimulation test in childhood (mean age 12.8+/-2.6 years) were retested at completion of linear growth (mean age 21.0+/-3.0 years), 4.6+/-1.6 years after discontinuation of hGH therapy. RESULTS: At the initial diagnosis, seven had complete and two had partial GH deficiency. At diagnosis, the mean peak GH response to ITT and dopamine was 4.8+/-4.08 and 3.4+/-2.9 mU/L, respectively. At retesting, the mean GH response to ITT and dopamine stimulation was 3.5+/-2.5 and 3.3+/-3.1 mU/L, respectively (P=0.91 and 0.96, respectively). During hGH therapy, mean height velocity increased from 3.5+/-1.9 cm/year at diagnosis to 9.9+/-3.64 cm/year during the first year (P=0.002). One of nine children diagnosed as having GH insufficiency who was treated with hGH replacement had normal growth hormone secretion at completion of linear growth. CONCLUSIONS: All GH-insufficient children should be retested after completion of their hGH treatment and linear growth to identify those who are truly GH insufficient and who may benefit from GH therapy in adulthood.     

Growth hormone response to hpGRF-40 in different forms of growth retardation and endocrine-metabolic diseases

The effect of one of the new human pancreatic growth hormone releasing factors (hpGRFs) was assessed in children or young adults with different forms of growth retardation or endocrine-metabolic diseases. Intravenously administered synthetic hpGRF-40 (1 g/kg) induced a clear-cut and prompt rise in plasma growth hormone (GH) levels in 8 normal prepubertal children and a definite GH rise in 11 out of 14 children with isolated GH deficiency (IGHD) and one child with the Silver-Russel syndrome. In two out of three subjects with craniopharyngioma hpGRF-40 did not induce any plasma GH increase.In seven out of ten children with constitutional growth delay (CGD), hpGRF-40 induced a biphasic GH response, with a prompt small GH increment followed by a second, more consistent rise. Both in children with IGHD and with CGD the rise in plasma GH following hpGRF-40 was markedly lower than in controls. In children with CGD the GH response to hpGRF-40 was defective, despite the fact that in most of them the GH response to standard pharmacological stimuli was normal according to generally accepted criteria.hpGRF induced a small but sustained plasma GH rise in four hypothyroid subjects, while in three out of four children with idiopathic obesity the GH response to hpGRF was strikingly reduced. These data demonstrate that hpGRF is a potent stimulus of GH release in normal prepubertal children and a physiological means of investigating GH function in diseases associated with growth impairment.Abbreviations hpGRF human pancreatic growth hormone releasing factor - IGHD isolated growth hormone deficiency - CGD costitutional growth delay - GH growth hormone - GRF growth hormone releasing factor - YR years - LHRH luteinizing hormone releasing hormone - ACTH adreno-corticotropic hormone - TRH thyrotropin releasing hormone - IU international units - SDS standard deviation score - LH lutcinizing hormone - FSH follicle stimulating hormone - TSH thyrotropin hormone - T₃ thriiodotyronine - T₄ Tyroxine - RIA radioimmunoassay - SE standard error - A adult - IBW ideal body weight - RT replacement therapy - PH primary hypothyroidism - CT computed tomography Paper presented in part at the 7th International Congress of Endocrinology, July 1–7, 1984, Quebec City, Canada     

The effects of cranial irradiation on growth hormone secretion

Growth hormone (GH) secretion has been studied under physiological conditions and in response to standard pharmacological stimuli in 14 children, who had previously received cranial irradiation between two and fourteen years earlier. All fourteen showed a blunted GH response to insulin hypoglycaemia and, in twelve, the GH response to arginine stimulation was also subnormal. Physiological GH secretion was studied by measuring integrated GH concentrations in 30 min blood samples collected over a 24 hour period by a continuous withdrawal pump. Compared to normal controls (n = 5), the irradiated patients showed a significant reduction in the mean integrated GH concentration (2.2: 8.8 mU/l; p less than 0.002), the total 24 hour GH output (mean 105.7 mU vs. 391.7 mU; p less than 0.002) and the mean GH output during the first six hours of sleep (mean 48.2 mU vs. 226 mU; p less than 0.002). There was no significant correlation between the maximum peak GH response to either pharmacological test and the total 24 hour GH output. Conventionally most short children undergo two provocative tests of GH release and if the GH response to one of the two tests is normal, it is usually assumed that GH production is adequate. Adopting these criteria in this study it would have been assumed incorrectly that GH production was normal in two children. Nonetheless all 14 children showed a blunted GH response to an ITT as well as a reduced total 24 hour GH output.(ABSTRACT TRUNCATED AT 250 WORDS)     

Plasma growth hormone response to growth hormone-releasing hexapeptide (GH-RP-6) in children with short stature

Eighteen children with short stature were evaluated for growth hormone (GH) reserve after pharmacological tests and a single iv injection of GH-RP-6. These children were divided into two groups: 10 were diagnosed as having idiopathic GH deficiency by classical stimulation tests (group A) and the remaining 8 (group B) were considered growth-retarded children with normal GH secretion, following conventional stimulation, but reduced endogenous GH secretion. The results were compared with a group of 12 normal children. As a group, patients in group A showed a lower GH response to GH-RP-6, while patients in group B had a similar response as normal controls. However, on an individual basis, a considerable degree of overlapping in responses among the three groups was evident. These data indicate that, on an individual basis, GH-RP-6 testing is not of diagnostic value in children suspected of having idiopathic GH deficiency.GH deficiency, GH-RP-6, short stature C Dieguez, PO Box 563, 15705 Santiago de Compostela, Spain     

Specific abnormalities in a visual motor psychological test in short children with abnormal growth hormone secretion

Forty short (< -2SD) prepubertal children with no organic disease underwent two growth hormone (GH)-stimulation tests, a sleep test and a psychological assessment based on the Rey-Osterrieth figure that was scored for boundary-type errors (defined as non-developmental severe distortions or disrespect of boundaries) by a psychologist who had not met the child. Twenty-three children had normal endocrinological findings and 17 had abnormal GH secretion (4 with complete GH deficiency and 13 with normal GH response to pharmacological stimuli but abnormal nocturnal secretion). Seventeen children had normal results in the Rey-Osterrieth figure test and 23 made boundary-type errors. The biological and psychological analyses agreed in 32 cases, leading to a very significant ( p < 0.0005) relation. This study reveals that short children with abnormal GH secretion, particularly low nocturnal secretion, show abnormalities independent of their developmental quotient in a visual motor psychological test.     

Twelve-hour spontaneous nocturnal growth hormone secretion in growth retarded patients

Twelve-hour nocturnal GH secretion was studied in 30 children with familial short stature (FSS), constitutional growth delay (CGD), total growth hormone deficiency (TGHD), partial growth hormone deficiency (PGHD), or idiopathic short stature (ISS). No difference was observed between subjects with FSS and children with CGD. The mean 12-hour serum GH concentration was significantly lower in patients with TGHD (p less than 0.001), children with PGHD (p less than 0.01), and subjects with ISS (p less than 0.01) than in subjects with FSS and CGD. No overlap was observed between the range of mean concentration values of children with TGHD and that of subjects with FSS. A significant correlation was found between growth velocity expressed as SD from the mean for bone age and GH concentration (p less than 0.001). All patients with a growth velocity less than 3rd percentile for bone age showed a mean nocturnal concentration less than 4 ng/ml. These data suggest that evaluation of 12-hour spontaneous nocturnal GH secretion with GH sampling every 30 minutes can be usefully employed in the diagnosis of GH deficiency.     

Growth hormone secretion following administration of growth hormone releasing hormone in constitutional short stature and idiopathic growth hormone deficiency

A stimulation test using 1 microgram growth-hormone-releasing factor (GRF 1-29 X NH2)/kg bodyweight was performed in children with familial short stature and in children with constitutional delay of growth and development. The GH secretion induced by this means was not different in these groups, but there was a difference in the response between normal children and children with idiopathic growth hormone deficiency (GHD). GH secretion after GRF administration was significantly lower in the GHD group than in the other groups. However, 6 of 24 patients with GHD responded to the test with a normal increase in GH (greater than 10 ng/ml), and 11 with an intermediate response (2-10 ng/ml). Thus, the test does not differentiate individual patients with defective growth hormone secretion from normal short children.     

Prediction of the growth response of short prepubertal children treated with growth hormone

The aim of this study was to identify predictors of the growth response to growth hormone (GH) during the first 2 years of GH treatment, using auxological data and the maximum GH response (GH_max) to provocation tests. The patients were 169 prepubertal short children (27F, 142M), with Gmax values ranging from 0 to 65 mU/1. Their mean age (± SD)was8.3 ± 2.4 years (range 3-13 years), mean height SDS –3.0 ± 0.7 (range –1.5 to –6.0SDS) and mean pretreatment height velocity was normal (± 0.0 SDS) (range -1.6 to + 0.9 SDS). The increase in height SDS during the first 2 years of GH treatment (0.1 U/kg/day) varied from 0.10 to 3.75 SDS, with younger children having a better growth response. Individual growth responses correlated (p < 0.001) with GH_max (r =–0.37), age (r= -0.35), 1-year pretreatment delta SDS (r = -0.25), mid-parental height SDS (r = 0.34), height SDS at start of treatment (r =–0.22) and difference between height SDS of an individual child at the onset of GH treatment and mid-parental height expressed in SDS (diff SDS) (r = –0.43). In a multiple stepwise linear regression model, diff SDS and log GH_max were found to be the strongest predictors of the magnitude of the growth response. In the short children in this study who exhibited a broad range of GH_max values, 33% of the growth response during the first 2 years of treatment could be predicted.     

Growth Hormone Treatment in Non-Growth Hormone-Deficient Children: Effects of Stopping Treatment

ABSTRACT. Overnight physiological growth hormone (GH) secretion was evaluated in 95 short, prepubertal children (73 boys, 22 girls). All the children were below the 3rd centile for height and achieved CH levels greater than 15 mU/1 following pharmacological stimulation. The mean average GH level was 7.1 mU/l and the mean sum of pulse amplitudes 80.4 mU/l. No relationship was found between age, height or height velocity and any of the parameters of GH secretion. The group was randomized to receive placebo, GH or remain under observation for the first 6 months and then all patients received GH treatment for a further 6 months. Those treated with GH, 0.27 IU/kg (0.1 mg/kg) three times weekly, in the first phase. demonstrated a mean increase in height velocity SDS of 3.24. There was no difference in growth response between the placebo or observation groups. In the second 6-month period. all children received GH according to the same dose regimen: they were then observed for a further 6 months following its discontinuation. In the 6 months following withdrawal of GH, all groups showed a significant fall in height velocity SDS, which returned to pretreatment levels, without demonstrating'catch-down'growth. Repeat sampling of overnight GH secretion within 3 days of discontinuing GH showed normal secretory patterns with a small reduction in mean peak amplitude. These results suggest that short children without classic GH insufficiency respond well to exogenous GH in the short term and return to pretreatment height velocities afterwards. Consequently, it may be possible to increase final adult height in such children by GH treatment.     

Reduced spontaneous growth hormone secretion in patients with Turner's syndrome

We evaluated growth hormone (GH) secretion in 81 patients with Turner's syndrome (TS) (mean age 10.7+/-3.6 y) with respect to karyotype, auxological characteristics and growth response to GH treatment (1 IU/kg/wk). None of the patients had spontaneous puberty or had started replacement therapy with estrogens. Thirty-nine patients (48%) had monosomia 45X, 29 (36%) structural abnormalities of the X chromosome and 13 (16%) X mosaicism. Before the start of GH therapy, each patient underwent an evaluation of mean nocturnal GH concentration (MGHC) and 75 patients also underwent 2 pharmacological tests. MGHC of the TS patients did not differ from that of 29 prepubertal GH-deficient girls (GH peaks < 8 microg/l after pharmacological tests) and both groups were lower (p < 0.0001 and p < 0.0005, respectively) than MGHCs of 27 short normal girls (GH peak > 8 microg/l). MGHC of the patients with TS was negatively correlated (p < 0.001) with bodyweight excess (BWE) at multiple regression analysis. MGHC of the TS patients with BWE < 20% was significantly higher (p < 0.02) than that of the TS patients with BWE > 20%, but again did not differ from that of the GH-deficient patients and was lower (p < 0.001) than that of the short normal girls. MGHC did not significantly differ between the 3 groups subdivided according to karyotype. Forty-four percent of the TS patients showed GH responses to pharmacological tests < 8 microg/l. Height velocity SDS at first and second year of therapy was not influenced by MGHC levels, chronological or bone age, target height or BWE. In conclusion, spontaneous secretion in our patients with TS was lower than that of the short normal prepubertal girls and did not differ from that of GH-deficient subjects, even if we excluded overweight patients. The level of GH secretion was unable to predict GH response to treatment.     

Growth response to human growth hormone treatment in children with partial and total growth hormone deficiency

The growth response during the first and second years of human growth hormone (hGH) treatment was studied in 14 prepubertal children with so-called "partial" GH deficiency (peak GH between 8 and 15 mU/l) and compared to 28 prepubertal children with "total" GH deficiency (peak GH less than 8 mU/l). There was no difference in growth acceleration between children with partial and total GH deficiency, when initial covariables were taken into account. In a stepwise multiple regression analysis initial stature, pre-treatment growth velocity and skinfold thickness were shown to be most related to growth response, but after exclusion of 3 children with a genetic form of total GH deficiency and partial TSH deficiency this relationship was lost. GH levels during provocation tests and auxological criteria have a poor predictive value for growth response to hGH therapy.     

Growth hormone testing in short children and their response to growth hormone therapy

Because current concepts of growth hormone (GH) testing and GH treatment have become controversial, we investigated the GH secretory patterns in children with normal and short stature. Twenty-four-hour serum GH levels were evaluated in three groups of children. Group 1 was composed of children with normal height (mean height = 0.02 SD, n = 33); group 2 was composed of short children (less than 5th percentile, n = 63) with normal results on provocative GH testing; and group 3 was composed of short children (less than 5th percentile, n = 7) with subnormal results on provocative GH testing. Mean +/- SD (range) GH levels during 24-hour studies of GH secretion were 1.6 +/- 1.1 (0.5 to 5.6), 1.8 +/- 1.2 (0.6 to 6.3), and 0.9 +/- 0.4 (0.5 to 1.7) ng/ml in groups 1, 2, and 3, respectively. No statistical difference existed in mean GH levels between groups 1 and 2 or between groups 1 and 3. The mean GH concentration from 24-hour studies in group 2 children did not correlate with chronologic age, height standard deviation, growth rates, or insulin-like growth factor 1 levels. The linear growth rate of 26 of 28 children in group 2 who received GH therapy for 6 months improved by 2 cm/yr or more; the mean +/- SD growth rate was 4.0 +/- 1.3 and 8.8 +/- 2.0 cm/yr during control and treatment periods, respectively, for these 28 children. Mean GH levels from testing did not predict response to GH during 6 months of therapy. Children with slower growth rates responded better to GH therapy (p less than 0.05). We conclude that (1) in 24-hour studies, GH levels in normal children overlapped with those of short children, including those with classic GH deficiency, (2) in 24-hour studies, GH levels did not predict responses of linear growth to short-term GH treatment, nor did they correlate with children's heights or growth velocities, and (3) the majority of short children in group 2 treated with GH for 6 months had an increase in linear growth velocity, the mean +/- SD change being 4.8 +/- 2.0 cm/yr.