The use--and misuse--of growth hormone

Recombinant growth hormone is an effective treatment for many children with short stature, but certainly not for all of them. The approach outlined here will help you make the right choices.     

The diagnosis of childhood growth hormone insufficiency and growth hormone resistance

Growth hormone insufficiency (GHI) is an uncommon though treatable cause of retarded growth velocity and short stature in childhood, the diagnosis generally requiring the demonstration of a subnormal growth hormone (GH) response to a physiological or pharmacological stimulus. Physiological and pharmacological GH release is a continuous variable and the relationship between spontaneous GH secretion and height velocity is asymptotic. Cut-off points for defining GH insufficiency are largely derived from adult observations, but have been extrapolated to children, for whom normative data are relatively scanty. There is no absolute cut-off that discriminates between normal and abnormal GH response. Moreover, poor reproducibility, sensitivity and specificity of the many dynamic tests available, particularly when performed in the very young child or in early adolescence, together with the confounding effects of assay performance, further weaken the diagnostic efficiency of biochemical investigations. Between 20-40% of children retested at the completion of GH therapy demonstrate a normal GH response to a provocative stimulus. Such limitations mitigate against over-reliance on GH provocation tests in diagnosis, and further emphasize the importance of careful auxology in evaluating the short child.     

The thyroid hormone system in mucoviscidosis

Endocrine disorders do not represent primary manifestations in children with cystic fibrosis. Abnormal thyroid gland function is commonly observed in patients with chronic nonthyroidal illnesses. Serum concentrations of TSH, T4 and T3 were measured and a TRH-stimulation test (200 micrograms Relefact per kg body weight) was performed in 24 patients with CF 6 to 16 1/2 years of age. As compared to the controls, CF patients had increased basal TSH and lower T4 and T3 concentrations. Finally they exhibited higher TRH-stimulated TSH and decreased peripheral T4 and T3. There was no correlation to the nutritional status or the Shwachman scores. In all patients with CF albumin, TBG and TBPA were also normal. Our results indicate a subclinical hypothyroidism in CF. Routine therapy with thyroid hormones is neither necessary nor recommended.     

重组人生长激素治疗生长激素缺乏症疗效观察

目的 观察基因重组人生长激素(rhGH)对生长激素缺乏症(GHD)患儿的疗效。方法 对15例GHD患儿应用rhGH治疗,每晚睡前皮下注射0.1 IU/kg,疗程6个月。结果 患儿身高由治疗前109.3±9.9cm增加到115.5±11.3 cm;年身高生长速度由治疗前2.8±0.6cm/年增加到11.6±3.5cm/年。治疗期间除少数患儿出现亚临床甲状腺功能低下,注射部位有轻度反应外,未发现明显副作用。结论 皮下注射rhGH是治疗儿童GHD的一种安全有效的方法。     

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.     

Growth hormone releasing hormone and growth hormone: genetic studies in familial growth hormone deficiency

Four families with growth hormone (GH) deficiency, either isolated or with other pituitary hormonal deficits are described. Members of each underwent pharmacological testing for GH secretion and infusions of GH releasing hormone (GHRH) to determine the locus of the defect in GH secretion. In addition, we have extracted DNA from white blood cells to characterize the GHRH and GH genes. All members tested had the normal complement of GH and GHRH genes. Four generations of one family with isolated GH deficiency, autosomal dominant were studied. The younger members showed minimal GH responsiveness to a single infusion of GHRH. However, the older members did not respond even after 30 doses of GHRH given intravenously every 3 h. Two members of a family with the autosomal recessive type of isolated GH deficiency had large GH increases after GHRH infusion. Thus in these families the GH secretory defect lies within the hypothalamus. Members of two families with pituitary deficiency (GH and other tropic hormones) of the autosomal recessive type had variable responses to GHRH and varying amounts of pituitary tissue seen on high resolution CT scans. Although it is not possible to delineate the precise location of the secretory defects in these latter two families, a hypothalamic defect is probable based on the responses to multiple trophic stimuli. Heterogeneity of structure and function exists within and between families with isolated GH deficiency and within and among families with pituitary deficiency. It is from the study of such families in which all members presumably have the same underlying defect that one can more readily decide on a pathogenetic mechanism.     

Comparison of growth hormone releasing hormone therapy and growth hormone therapy in growth hormone deficiency

Seven children with growth hormone deficiency of hypothalamic origin responded to an i.v. bolus of growth hormone releasing hormone (GHRH) (1–29)-NH2 with a mean serum increase of 10.7 ng/ml growth hormone (GH) (range 2.5–29.3 ng/ml). Continuous s.c. administration of GHRH of 4–6 g/kg twice daily for at least 6 months did not improve the growth rate in five of the patients. One patient increased his growth rate from 1.9 to 3.8 cm/year and another from 3.5 to 8.2 cm/year; however, the growth rate of the latter patient then decreased to 5.4 cm/year. When treatment was changed to recombinant human growth hormone (rhGH) in a dose of 2 U/m² daily, given s.c. at bedtime, the growth rate improved in all patients to a mean of 8.5 cm/year (range: 6.2 to 14.6). Presently GHRH cannot be recommended for the routine therapy of children with growth hormone deficiency since a single daily dose of rhGH produced catch-up growth which GHRH therapy did not.Abbreviations GH growth hormone - GHD growth hormone deficiency - GHRH growth hormone releasing hormone - hGH human growth hormone - rhGH recombinant human growth hormone - SM C/IGF I somatomedin C/insulin-like growth factor I On the occasion of the 85th birthday of Prof. Dr.Dr.h.c. mult. Adolf Butenandt     

The dosage dependency of growth and maturity in growth hormone deficiency treated with human growth hormone

A group of 11 pre-pubertal growth hormone deficient patients were treated with human growth hormone over a period of 4 years. In 6 of the patients the dosage was 4 IU 3 times a week and in 5, 8 IU 3 times a week. Changes in height demonstrated that the "catch up" was significantly greater and of longer duration in the second group. In spite of a more rapid increase of bone age in the second group, the prognosis of final height had improved significantly at the end of the study period. A comparative study of the plasma concentrations significantly at the end of the study period. A comparative study of the plasma concentrations of T4, TSH, gonadotrophins and steroids, to see if the greater velocity of bone maturity in the second group could be due to contamination of the preparation by other could be due to contamination of the preparation by other hypophysary hormones, did not demonstrate significant differences between the groups.     

Growth hormone releasing hormone. Review

Growth hormone-releasing hormone was isolated 1982 from human pancreatic tumours. They were found to consist of three peptides (GHRH1-44, GHRH1-40, GHRH1-37) which in vivo and in vitro were specific stimulators of pituitary growth hormone secretion. These tumor-derived GHRHs were demonstrated to be identical to human hypothalamic GHRHs. Extrahypothalamic GHRH is present in some brain regions and in the gastrointestinal tract. Circulating GHRH is detectable in human plasma, but little is known about its function. Above all binding of GHRH to a specific receptor stimulates growth hormone secretion through formation of cyclic AMP. GHRH secretion is modulated by somatostatin, the somatomedins and growth hormone itself. Following single injection of GHRH1-44 i.v. the equilibration half-time is 1.0 +/- 0.2 min and elimination half-time is 6.8 +/- 1.2 min. Maximal growth hormone response is achieved after injection of 1 microgram/kg GHRH. Using higher GHRH-doses growth hormone can be stimulated via subcutaneous or intranasal application. A single i.v. GHRH-test is not sufficient to prove a pituitary defect since growth hormone can be stimulated following repetitive injections in some cases. About 50% of patients with growth hormone deficiency have a hypothalamic defect of GHRH release. In some of these patients GHRH s.c. can promote linear growth to the same degree as growth hormone treatment.     

Growth hormone deficiency in a child with Williams-Beuren syndrome. The response to growth hormone therapy

Pre- and postnatal growth retardation of unknown pathogenesis is a common clinical feature in patients with Williams-Beuren syndrome (WBS). However, growth hormone deficiency (GHD) has not been considered a major cause of growth retardation. There is only one patient in the literature with confirmed GHD who responded well to human growth hormone (hGH) therapy. We report a female infant with confirmed WBS who, through provocative testing, was found to have GHD and who responded satisfactorily to hGH therapy. Height SDS was -4.2 at the age of 12 months when hGH was initiated and increased to -0.8 at the age of 4.25 years. The pathogenesis of GHD in our patient is unclear. Nevertheless, the elevated levels of prolactin and the response of hGH to growth hormone releasing hormone (GHRH) administration are indicative of a hypothalamic rather than pituitary defect. In conclusion, GH deficiency might contribute to the growth failure in a number of patients with WBS and in such cases hGH therapy will most likely improve final height.     

Turner综合征的生长激素水平

目的：探讨Turner综合征的生长激素水平和人生长激素治疗效果．方法对不同核型的Turner综合征患者19例进行生长激素激发试验，并对部分对象7例用人生长激素治疗。结果生长激素完全缺乏者9例，部分缺乏者8例，正常2例。接受人生长激素治疗7例，治疗前年增长速率均≤2cm，治疗后较前有所增长，效果最好者7个月增长5．6cm。结论Turner综合征的矮小与生长激素水平有一定的关系，用人生长激素治疗能使之改善。     

The hormone pattern in a case of arrhenoblastoma

A case of ovarian arrhenoblastoma in a 14-year-old girl is reported. The patient presented with primary amenorrhea, severe diffuse hirsutism, moderate clitorial enlargement and slight decrease in breast size. Hormonal examinations revealed high plasma testosterone and androstenedione levels, normal plasma prolactin, dehydroepiandrosterone-sulphate, 17-alpha-hydroxyprogesterone, urinary 17 ketosteroids and pregnanetriol and low plasma 17 beta oestradiol, oestrone, FSH and LH.Androgen concentrations decreased under dexamethasone suppression test. Following tumour ablation menses occurred spontaneously and normal hormone patterns were observed.