Comparison of single and combined tests for the evaluation of plasma growth hormone secretion in normal short children

Growth hormone (GH) response to provocative tests was compared in normal short children. Seven of 23 children failed to respond to insulin hypoglycemia. Using insulin hypoglycemia followed by L-dopa only 2 of 23 children did not respond and giving bromocriptine combined with insulin hypoglycemia only 1 of 8 children failed to respond. All children submitted to propranolol followed by exercise (n = 14) and to bromocriptine followed by exercise (n = 6) responded with a satisfactory increase in plasma GH levels. The increase elicited by propranolol and exercise was higher than that induced by insulin hypoglycemia alone (p less than 0.005), exercise alone (p less than 0.05) or L-dopa after insulin hypoglycemia (p less than 0.01). The rise of GH induced by bromocriptine and exercise was higher than that obtained with insulin hypoglycemia alone (p less than 0.05). This study suggests that both adrenergic and dopaminergic mechanisms are involved in exercise induced GH release and confirms that combined tests are more useful than a single test to evaluate GH secretion.

Steroid metabolism by a tumour of the specific gonadal stroma in a child

A study of steroid metabolism by a tumour of the specific gonadal stroma was carried out in a 10 year old boy. Tumours developed in the two testes from multiple foci, and clinically, no signs of sexual development were evident. Four testicular enzymes necessary for testosterone biosynthesis were estimated in the child, in two adult controls, and in three pre-pubertal boys with male pseudohermaphroditism but normal tests of Leydig cell function. 17 alpha-Hydroxylase and 17 beta-hydroxysteroid dehydrogenase were similar in the five controls and in the gonad with the tumour, while 17,20-desmolase and 3 beta-hydroxysteroid dehydrogenase were grossly deficient in the child with the tumour. These enzyme deficiencies might explain the absence of peripheral virilization in a boy with a tumour of Leydig and Sertoli cells.

Evaluation of short stature in children

Within a year 429 children referred for short stature have been evaluated. The age at consultation ranged from 5 months to 17 1/2 years. Healthy but small children came at 5 to 7 and 10 to 13 years, while those with different pathologies attended the clinic at all ages. The stature of 43% of the investigated children ranged within normal limits (till -2 SDS), while 57% had a small stature. 68% of the children could be considered healthy, 32% had different endocrine and nonendocrine diseases responsible for their growth retardation. Retarded bone age (greater than 2 SD below the mean) was observed in 65% of the significantly short but otherwise healthy children and in only 28% of the healthy children with heights above -2 SD. Extreme short stature was mainly associated with a recognized disease of chronic and genetic origin, low birthweight and malnutrition. The high incidence of hypopituitarism (15 patients) is due to the fact that this study was performed in an endocrine clinic.

Effects of alpha-bromoergocryptine on pituitary hormone secretion in children

The effect of bromoergocryptine (BE) on human GH (hGH), PRL, LH, FSH, TSH, and blood sugar levels was evaluated in a series of 22 normal children. Blood samples were collected in basal conditions and after 30, 60, 90, 120, 150, and 180 min of BE administration (1.25 or 0.62 mg/os). The drug induced a marked and sustained increase in hGH secretion when basal serum levels of the hormone were lower than 10.0 ng/ml (n = 15). When basal hGH serum levels were higher (n = 7), BE provoked either a later increase of serum hGH in most children (n = 5) or a persistent decrease in hGH (n = 2). On the other hand, BE markedly inhibited PRL secretion without modifying LH, FSH, or TSH. The data obtained suggest that BE can be used as a useful tool for the assessment of hGH secretion in children.

Effect of gonadotrophins and testosterone on the seminiferous tubules of the immature rat

The actions of HCG and PMSG for different periods and of testosterone of the immature rat testis were studied. Short-term administration of HCG (1-3 days) induced an early meiotic and postmeiotic stimulatory effect but a decrease in spermatogonial numbers. Administration of HCG for longer periods (10 days) caused a reduction in numbers of all cell types. Treatment with HCG + PMSG reduced the amount of inhibition, while PMSG alone resulted in histological and humoral signs of stimulation of the interstitial tissue and the meiotic and postmeiotic stages; the numbers of spermatogonia were not affected. Testosterone caused stimulation of the meiotic and postmeiotic stages and a reduced number of spermatogonia. It is concluded that while PMSG directly stimulates spermatogonia, HCG acts through testosterone secretion at the meiotic and postmeiotic stages. The early inhibitory effects of HCG and testosterone on spermatogonial numbers could be ascribed to the inhibition of endogenous FSH by androgens.

Effect of HCG on the interstitial cells and androgen production in the immature rat testis

The effect on the interstitial cells in the immature rat testis of administration of HCG for different periods was correlated with testosterone plasma levels. Significant and progressive stimulation of mitosis was observed after 3 days of HCG treatment but stabilization occurred after 5 days. The numbers of precursor fibroblasts had increased by the 5th day and were still increasing by the 10th day of treatment. Numbers of Leydig cells were significantly greater at 5 and 10 days of treatment. Plasma testosterone showed a progressive and continuous increase in all groups. The increase in Leydig cell number is considered to be due to a combination of increased stimulation of mitoses in Leydig cells and differentiation of precursor fibroblasts. Mitosis seems to precede fibroblastic differentiation, but the latter continues when mitotic changes have stabilized. The elevation of plasma testosterone concentrations is probably due firstly to the stimulation of the existing Leydig cells and then to the increase in the number of hormone-secreting cells.

Plasma concentration of oestradiol-17beta in premature thelarche and in different types of sexual precocity

Plasma Oe2 concentration was measured by radioimmunoassay in patients with premature thelarche, with precocious puberty and in 29 normal controls. The mean plasma Oe2 was 1.5 pg/ml (0-7.2) in normal prepubertal girls, 23.8 +/- 17.8 (SD) in pubertal girls, 50.2 (+/- 19.4) in the follicular phase, and 94.2 (+/- 19.5) in the luteal phase of normal adult females. Ten girls with premature thelarche had a mean of 7.7 +/- 6.6 pg/ml. Three of them showed higher values than the other 7, suggesting that in these cases, elevated levels of plasma Oe2 might have played a role in the development of breast tissue. Ten untreated girls with idiopathic precocious sexual development had a mean of 51.6 +/- 42.9 pg/ml while 6 patients treated with 150 mg per week of medroxyprogesterone acetate had a mean of 11.4 +/- 2.5 pg/ml. Two patients with Down's syndrome, hypothyroidism and sexual precocity had plasma Oe2 of 144 and 31.5 which fell to 24.7 and 8 pg/ml, respectively, after thyroid replacement. One girl with a granulosa cell tumour had a basal value of 304 pg/ml and a concentration of 27 pg/ml after surgery.

Gonadotropin secretion in prepubertal and pubertal primary hypogonadism: response to LHRH

Plasma LH and FSH were measured before and after LHRH administration in 10 patients with Turner's syndrome, in 7 with anorchia, in 2 castrates, in 18 with Klinefelter's syndrome, and in 11 prepubertal subjects with unilateral cryptochidism used as a control group. Basal LH was elevated in 4 and basal FSH in 8 of 10 patients with Turner's syndrome. Four patients with anorchia showed elevations of LH while FSH had increased in all of them. The two castrates had normal or slightly increased basal LH and definite elevations of FSH. Prepubertal subjects with Klinefelter's syndrome had normal plasma LH and FSH levels, but showed a marked elevation when they developed puberty. After LHRH administration, mean LH increased by 297% and FSH by 81% in Turner's syndrome, while in anorchia LH increased 757% and FSH 104%. After LHRH administration, patients with unilateral cryptorchidism had an LH increment of 316% and a FSH increment of 164%. Patients with prepubertal Klinefelter's syndrome showed elevations of 261% for LH and 221% for FSH after LHRH treatment. Adolescent subjects with Klinefelter's syndrome had an increment of 352% for LH and only 13% for FSH after LHRH administration. We have concluded that patients without functioning gonads fail to suppress gonadotropin secretion even before puberty while the gonads of the prepubertal Klinefelter's syndrome are able to control LH and FSH release. After puberty, in spite of the hypersection of LH and FSH observed in all subjects with agonadism there is a large pituitary reserve of the gonadotropins. We suggest that the relative inability of pubertal patients with Klinefelter's syndrome to increase FSH after LHRH treatment might be due to the presence of an abnormal compound secreted by the gonads.

Levels of plasma growth hormone in children with congenital heart disease

HGH plasma levels were studied in 45 children with different types of cyanotic and acyanotic congenital heart diseases with and without growth retardation. Median HGH levels in patients with normal height (Group I) were 5.2 ng/ml (range 0–50) and in patients with short stature (Group II) 7.2 ng/ml (range 0.6–50). No difference was found between these groups ("Z" = 1.33, P: non-significant). However on comparing the cyanotic and acyanotic patients regardless of the presence of growth retardation, HGH levels were significantly different (P < 0.01). The acyanotic group with an oxygen saturation of 94.4 % ± 1.7 (mean ± se) had HGH levels of 4.6 ± 0.7 ng/ml. The cyanotic group with an oxygen saturation of 69.5 % ± 4.4 had HGH levels of 23.3 ng/ml ± 3.5. An insulin test was performed in 5 patients with high HGH basal levels. Three showed an increase of HGH levels after insulin. In the other 2 patients the HGH levels remained high.

In conclusion growth hormone deficiency could be ruled out as a possible cause of growth retardation in children with congenital heart disease. It is suggested that hypoxia could induce HGH secretion. Tissue hypoxia and its effect on DNA metabolism could be a factor which regulates HGH production. Hypoxia could also stimulate anaerobic metabolism and the resultant metabolites bring about an increase in HGH release.

The testis in patients with abnormalities of sex differentiation. Histology and endocrine function

Testicular function was studied in 18 patients with abnormalities of sexual differentiation. Fourteen patients were prepubertal and four postpubertal. Plasma testosterone was determined before and after 5000 IU HCG administered daily during 5' days. Of the fourteen prepubertal patients, the two true hermaphrodites and the patient with asymmetrical gonadal differentiation showed a poor response to gonadotrophin stimulation. This could be explained by the small amount of active testicular tissue or its coexistence with ovarian and rudimentary gonadal tissue which might exert some influence on the endocrine function of the testis. In the group of eight patients with male pseudo-hermaphroditism and ambiguous external genitalia, the response to HCG showed a large variation. The three patients with small testes had lowest values i. e. 210, 198 and 192 ng/100 ml. The remaining five patients showed normal values ranging between 360 and 720 ng/100 ml. The ambiguous external genitalia of these patients could be explained as being due to a diminished androgen target organ sensitivity limited to the external genitalia. The three prepubertal patients with male pseudo-hermaphroditism and female external genitalia showed a marked increase in plasma testosterone with HCG ranging between 598 and 1100 ng/100 ml. The four pubertal cases also had high values in basal conditions, between 920 and 1870, which increased even more after gonadotrophin stimulation, in one case from 1382 to 2264 ng/100 ml. This hypersensitivity to exogenous HCG, even in infancy, correlates with the elevated basal values observed in adult patients with otherwise female external genitalia and androgen insensitivity. Finally, the HCG stimulation test could be useful for the demonstration of testicular tissue in prepubertal patient with abnormalities of sexual differentiation, although it cannot be used as a prognosis of masculinization or feminization at puberty.