Rapid effect of intravenous growth hormone (GH)-releasing hormone 1–44 on plasma GH levels in children

Growth hormone releasing hormone (GHRH)-testing was performed in 24 short normal children (16 male, 8 female). Before and after administration of GHRH_1–44 (1g/kg body weight i.v.) blood samples for growth hormone (GH) determination were drawn at-30, 0, 1, 2, 3, 4, 6, 8, 10, 15, 30, 45, 60, and 90 min. Plasma GH increase was apparent 1 min after injection and in 12 patients (7 female) peak plasma GH values were reached within 15 min. In all patients plasma GH levels were greater than 10 ng/ml within the first 8 min following GHRH injection, but in 4 patients this level was not attained when considering only GH values obtained after 15 min. These results demonstrate the capability of the pituitary to rapidly secerete GH in response to GHRH_1–44 in children. Therefore, in this age group blood samples for GH determination should be taken earlier when testing with GHRH_1–44.Abbreviations GHRH growth hormone releasing hormone - GH growth hormone - SD standard deviation     

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.     

Diagnostic value of growth hormone-releasing hormone test in children and adolescents with idiopathic growth hormone deficiency

Average growth hormone (GH) peaks following an i.v. growth hormone releasing hormone (GHRH) 1–29 stimulation test were significantly lower in 48 children and adolescents with GH deficiency (GHD) than in 20 age-matched controls (15.2+12.7 vs 37.5+28.1 ng/ml, 2P<0.001). Twelve patients exhibited a low GH peak (<5 ng/ml), 27 demonstrated a normal response (>10 ng/ml) and 9 showed an intermediate rise in plasma GH (5–10 ng/ml). Six of the 12 patients with low GH response to the first GHRH stimulation failed to respond to two other tests immediately before and after a 1 week priming with s.c. GHRH. These subjects with subnormal GH increase at repeat testing had total GHD (TGHD) and multiple pituitary hormone deficiency (MPHD) and had suffered from perinatal distress. On the contrary, 26 of 27 patients with normal GH response to the first test had isolated GHD and only a minority (8/27) had signs of perinatal distress. It is concluded that perinatal injuries primarily damage pituitary structures and that a pituitary defect more probably underlies more severe forms (TGHD and MPHD) of GHD.Presented in part at the 7th Meeting of the Italian Society for Paediatric Endocrinology (Milan, 20–21 October 1989)     

Growth response to growth hormone therapy following craniospinal irradiation

Nineteen (12 male, 7 female) children, who have received craniospinal irradiation for the treatment of a brain tumour distant from the hypothalamic-pituitary axis, resulting in growth hormone (GH) deficiency (CS-PRGHD), have been treated with GH. Eight have completed growth. Comparison has been made with the growth of seven untreated children, whose heights and growth rates at presentation were normal despite GH deficiency secondary to irradiation. GH produced a significant increase in growth velocity over the first 3 years' treatment in CS-PRGHD patients with a mean first year increment of 3 cm/year. Patients, treated to completion of growth, showed a significant increase in leg length standard deviation (SD) score (SDS+0.2) compared to that of the untreated (SDS–0.9) (P<0.05). Stitting height SD scores decreased irrespective of GH therapy (by -1.7 for the treated and -2.2 for the untreated). The onset of puberty in the irradiated patients occurred at a mean bone age of 10.7 years in males and 9.9 years in females. This limited the time available for GH therapy. These factors resulted in a decrease in standing height SDS of 0.9 at completion of GH therapy in CS-PRGHD, but a decrease of 1.7 in those not treated with GH. Thus GH therapy failed to induce catch-up growth in irradiated patients, but it did prevent further loss of adult stature, with a mean final height SD score of -3.4 in CS-PRGHD patients.Abbreviations GH growth hormone - CS-PRGHD post craniospinal irradiation growth hormone deficiency - change in - SDS standard deviation score - ALL acute lymphatic leukaemia - IGHD isolated growth hormone deficiency - C-PRGHD post cranial irradiation growth hormone deficiency - FSH follicle stimulating hormone - LH luteinising hormone - BA bone age - TSH thyroid stimulating hormone - CA chronological age     

Recombinant human growth hormone treatment in children with thalassemia major

BACKGROUND: To evaluate the growth hormone reserve and the growth hormone response to recombinant human growth hormone (GH) in prepubertal thalassemic children with growth retardation. METHODS: Twenty thalassemic patients with short stature and delayed bone age were studied. Patients were randomized into GH-treated (n = 10) and non-GH treated (control; n = 10) groups. The GH-treated group received recombinant human (rh)-GH (Genotropin) at the dose of 0.7 IU/kg per week for 12 months. RESULTS: There was a significant discordance between GH response to pharmacologic stimuli and physiological secretion of GH/GHRH testing. Following the administration of rhGH, growth velocity increased from 2.47 +/- 0.48 cm/year to 6.27 +/- 0.76 cm/year (P = 0.005), whereas there was not a similar change in the non-GH-treated group. The height velocities of the two groups during the 1 year follow-up period were significantly different (6.27 +/- 0.76 vs 3.99 +/- 0.34 cm/year; P = 0.025). There were significant differences between the height velocity improvements and height velocity standard deviation scores of the two groups as well. CONCLUSION: The present study has demonstrated that rhGH is a safe and efficacious mode of treatment in thalassemic children.     

Effect of two consecutive administrations of GHRH in children with constitutional growth delay

It has been suggested that children with constitutional growth delay might have a transient immaturity of the neurotransmitter pathways necessary for the control of growth hormone releasing hormone (GHRH) secretion. In this study we evaluated the effects of two consecutive GHRH boluses (1 g/kg, i.v.) in nine prepubertal boys with constitutional growth delay. Growth hormone (GH) responses to GHRH administration were similar to that observed in normal children (first GHRH bolus, GH net incremental area under the curve (nAUC) ±SE: 788±244 vs 984±242 ng/ml per hour; second bolus, GHnAUC: 657±122 vs 541±129 ng/ml per hour, respectively). These data suggest that no relevant abnormalities in the mechanisms determining the somatotroph sensitivity to GHRH are present in children with constitutional growth delay.     

Correlation between pituitary growth hormone reserve and degree of growth failure in children with short stature

The correlation between a releasable pituitary growth hormone (GH) pool and degree of growth failure was examined in 30 children with GH deficiency (group I) and 19 children with normal short stature (group II). Based on the responsiveness of GH to GH-releasing hormone (GHRH), group I, with low GH responses (below 7 ng/ml) to both insulin and arginine, was classified into three subgroups; I_a (peak value less than 10 ng/ml, n=19), I_b (10–20 ng/ml, n=5) and I_c (above 20 ng/ml, n=6). Group II, with a GH response above 10 ng/ml to either insulin or arginine, was also divided into II_a (below 20 ng/ml, n=5) and II_b (above 20 ng/ml, n=14). Body length and growth velocity in I_a and I_b were significantly reduced vs I_c; bone age in I_a was retarded vs I_c; plasma somatomedin C (Sm-C) levels in I_a and I_b were decreased vs I_c, who had almost normal levels (0.90±0.55 U/ml). The incidence of other combined pituitary hormone deficiencies and previous perinatal distress was definitely high in I_a and I_b, but zero in I_c. In group II also, body length and growth velocity were significantly decreased in II_a vs II_b (P<0.01). These results indicate that [1] the pituitary reserve of GH estimated by GHRH is a good reflection of the degree of growth failure in GH-deficient children as well as in those of normal short stature, [2] hypothalamic GHRH deficiency tends to have a milder effect on growth retardation than pituitary GH deficiency, and [3] normal short children with a diminished GH reserve may be potential candidates for the GH treatment.Abbreviations ACTH adrenocorticotropin - LH luteinizing hormone - LH-RH luteinizing hormone-releasing hormone - GH growth hormone - GHRH growth hormone-releasing hormone - Sm-C somatomedin C - TRH thyrotropin-releasing hormone - TSH thyrotropin     

Multicentric study of efficacy and safety of growth hormone use in growth hormone deficient children in India

Growth Hormone being very expensive in India data on use of recombinant human growth hormone (rhGH) is scarce. The authors studied the effect and safety of one year of therapy with rhGH on growth velocity and predicted final height in Indian patients with growth hormone deficiency (GHD). A multicentric, prospective, open trial with rhGH was performed on 15 patients. Patients received rhGH in a dose of 0.7 IU (0.23 mg)/Kg/week. The mean pretreatment height was 111.2cms {SD 12.4}, height velocity was 3.1 cms per year {1.2} and predicted height was 146.5 cms {10.4} at a mean age of 12.0 (2.8). At the end of therapy mean height was 123.4 {11.9}, height velocity was 12.1 cms per year {2.8} and the predicted height was 153.0 cm {9.4}. The increase in predicted height was thus 6.5cm (4.2). The increment in height velocity with growth hormone therapy was statistically significant (p value= 0.001). The present study shows that children with growth hormone deficiency in India also benefit from therapy with rhGH even when treatment is started late as compared to the published Western data and there is a potential for increased final height.     

Growth hormone therapy

Growth hormone (GH) therapy has revolutionized treatment of children with growth hormone deficiency (GHD). Improved height outcome with final height in the target height range has been achieved in these children. Identification of Creutzfeldt-Jakob disease, a deadly prion mediated disorder, in recipients of pituitary GH accelerated the transition from pituitary derived GH to recombinant GH. Once daily subcutaneous administration of the freeze-dried preparation at evening is the recommended mode of GH therapy. Studies have led to use of higher dose of GH for improving height outcome (0.33 mg/kg/week or 0.14 IU/kg/day) albeit at a significantly high cost. Growth velocity increases from 3–4 cm/year before therapy to 10–12 cm/year during the first two years of therapy and is maintained at 7–8 cm/year after a period of two years. Close follow-up with regular clinical and laboratory monitoring is essential for achieving a desirable height outcome. A theoretical unlimited supply has led to wide spread use of GH in a variety of disorders other than GHD. Initially started in children with Turner syndrome, GH has now been used in chronic renal failure, idiopathic short stature and intrauterine growth restriction besides a wide array of newly emerging indications.     

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     

Empty sella, growth hormone deficiency and pseudotumour cerebri: effect of initiation, withdrawal and resumption of growth hormone therapy

An 11- year-old boy with normal visus and eye fundus, but with empty sella, growth hormone (GH) deficiency and central diabetes insipidus was found to have intracranial hypertension with papilloedema after 6 months of catch-up growth under recombinant human GH (rhGH) replacement therapy. Withdrawal of rhGH therapy was associated with normalisation of intra‐cranial␣pressure within 1 week. Three months later, resumption of rhGH therapy at a lower dose was again followed by pronounced growth acceleration, but now without papilloedema. Conclusion Children with empty sella and GH deficiency may be prone to rhGH-induced pseudotumour cerebri which appears to be rapidly reversible and dose-dependent. Received: 4 August 1995 / 26 October 1995     

Growth and growth hormone in children during and after therapy for acute lymphoblastic leukaemia

Growth impairment and growth hormone (GH) deficiency have been reported in children treated for acute lymphoblastic leukaemia (ALL). We have studied growth and GH secretion in a group of 50 patients, affected by ALL, during a 2- to 5-year period after diagnosis, and in 12 long-term-survivors. We observed a significant decrease in growth velocity during the 1st year (in particular during the first 6 months) of therapy and a catch-up growth after the end of therapy. Longterm survivors did not exhibit a significant reduction of height standard deviation score (SDS), as compared to height SDS at diagnosis. None of the patients showed GH deficiency. Our data indicate that chemotherapy significantly affects growth of patients treated for ALL, whereas radiotherapy-at the doses used in this study-does not induce GH deficiency, at least not within 9 years after diagnosis.     

Growth hormone treatment of Turner syndrome patients with insufficient growth hormone response to pharmacological stimulation tests

Growth before and during treatment with biosynthetic human growth hormone (hGH) was studied in 13 patients with Turner syndrome (TS) and a growth hormone (GH) response of less than 10 g/l to two standard provocative tests. During 1 year of treatment with hGH (0.15 IU/kg per day) height velocity (mean±SD) increased significantly (P<0.001) from 3.7±1.8 cm/year to 7.6±1.5 cm/year. The auxological data in these girls before and during treatment with hGH were similar to those observed in TS patients with a normal response of GH to pharmacological stimuli. It is concluded that in girls with Turner syndrome GH testing should only be performed when height velocity is below the Turner norm. In TS patients with residual growth potential a clinically significant growth acceleration can be obtained with a higher-than-replacement dose of hGH, i.e. 0.15 IU/kg per day, regardless of GH testing.     

A comparative study of growth hormone (GH) and GH-releasing hormone(1–29)-NH2 for stimulation of growth in children with GH deficiency

In this study, 60 patients with proven growth hormone deficiency (GHD) of hypothalamic origin were randomized into three equal groups, and received growth hormone-releasing hormone(1–29)-NH, (GHRH(1–29)-NH,), 30 or 60 μg/kg/day, or growth hormone (GH), 0.1 IU/kg/day, for 6 months. There were no significant differences in growth between the two groups given GHRH(1–29)-NH, but growth in the GH group was significantly better than in the other two groups ( p < 0.01). Mean height velocities at 6 months were 9.2, 9.3 and 14.6 cm/year for the three groups, respectively. Plasma GHRH concentrations increased steadily over the 6-month treatment period, with higher levels in the group on the higher dose. During GHRH(1–29)-NH₂ treatment, serum concentrations of insulin-like growth factor I rose initially, but then fell to values similar to those before treatment. No GH antibodies were detected, but all 20 patients on high-dose GHRH(1–29)-NH, and 19 of 20 patients on low-dose GHRH(1–29)-NH₂ developed GHRH antibodies. These had almost disappeared by 9 months after stopping treatment. There was no correlation between antibody titres and increase in height. No serious side-effects were seen, but three patients receiving GHRH(1–29)-NH, reported mild irritation at the injection site. These results from the continuous infusion of GHRH(1–29)-NH₂ over 6 months suggest that this treatment, or the related use of a depot preparation, is unlikely to be as effective as GH for the promotion of growth in GHD.     

The effect of gonadotrophin releasing hormone analogue on height prognosis in growth hormone deficiency and normal puberty

We have treated seven pubertal children, five (three female, two male) with growth hormone deficiency and two (one female, one male) with constitutional short stature with intranasal (D-Serine⁶) gonadotrophin releasing hormone (GnRH) analogue (Buserelin) for a mean of 0.84 years (range, 0.5–1.3). Treatment was successful in arresting pubertal development but there was no improvement in final height prognosis.Abbreviations GnRH gonadotrophin releasing hormone - GH growth hormone     

Growth response to growth hormone therapy following cranial irradiation

The growth response to growth hormone (GH) therapy has been studied in 12 children who received irradiation to the cranium alone either for brain gliomas, distant from the hypothalamic-pituitary axis, or as prophylaxis against CNS leukaemia. Seven children have completed GH treatment (mean duration 4 years) and five are presently on GH (mean duration 1.2 years). This response has been compared to that seen in 14 children with isolated idiopathic GH deficiency (IGHD), following GH therapy. Before treatment, the cranially irradiated patients (C-PRGHD) had higher standard deviation scores (SDS) for standing height, sitting height and leg length, and less bone age (BA) retardation, but started treatment at a similar age, and with a similar pre-treatment growth velocity and GH peak to standard provocative tests, compared to IGHD patients. GH produced a significant and similar increase in growth velocity (cm/year and SDS for BA) over the first 2 years' treatment in both groups. However C-PRGHD patients entered puberty and thus completed growth earlier than the IGHD group. As a result, cranially-irradiated children showed no change in height SDS with GH therapy, compared to catch-up growth in IGHD. Nevertheless, GH has enabled C-PRGHD patients to maintain their centile position and to achieve a more acceptable final height.Abbreviations GH growth hormone - IGHD idiopathic growth hormone deficiency - C-PRGHD post cranial-irradiation growth hormone deficiency - SDS standard deviation score - BA bone age - ALL acute lymphatic leukaemia - TSH thyroid stimulating hormone - CA chronological age - HA height age     

Growth hormone deficiency of hypothalamic origin in septo-optic dysplasia

Hypothalamic pituitary function and growth hormone releasing hormone (GHRH) loading tests in two children with septo-optic dysplasia (SOD) revealed isolated GH deficiency in one and deficiencies of growth hormone, adrenocorticotropic hormone and antidiuretic hormone in the other. Secretion of GH was elicited in the first patient by single i.v. bolus administration of GHRH and after repetitive i.v. infusions of GHRH in the second. With these results we confirmed that the hypopituitarism in our patients with SOD was of hypothalamic origin. Both patients also had infantile spasms.     

Growth hormone secretion in children and adolescents with familial tall stature

Sixty-five patients (22 boys and 43 girls) presenting with familial tall stature were investigated with regard to growth hormone (GH) secretion, both physiological and after stimulation with thyrotropin releasing hormone (TRH) and growth hormone relasing hormone (GHRH). Plasma insulin-like growth factor-I (IGF-I) was also measured. Two groups of patients were distinguished according to their physiological secretion of GH: a high secretory group (n=49) with a mean 24 h integrated concentration of GH (IC-GH) of 5.4±2.3 g/l per minute and a large number of peaks (5.1±1.6 in 24 h), and a low secretory group (n=16) with a mean 24 h IC-GH of 2.1±0.5 g/l per minute and few peaks (3.3±1.3 in 24h). Plasma IGF-I levels and GH peak values after the TRH test were significantly higher in the high secretory group. These results indicate that familial tall stature is the consequence either of hypersecretion of GH or of hypersensivity to this hormone (IGF-I levels being normal in spite of low GH levels).     

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.     

Effects of long-term growth hormone releasing hormone 1 -29 in significantly short children

Seven children with significant idiopathic short stature (SISS) whose heights were significantly below the third percentile (SD score for height —2.5 to —3.5) and who had normal levels of growth hormone (GH) were treated with growth hormone releasing hormone (GH-RH) in a dose of 30 /μg/kg/day. Therapy was discontinued if patients failed to increase their rates of growth by more than 2.0 cm/year over their pre-therapy growth rate. Treatment was discontinued in two of the patients after 12 months but was continued in the other five for 24 months. These data demonstrate that some patients with SISS grow well during the first 2 years of treatment with GH-RH.