No abstract

During the past 11 y, 115 children younger than 8/9 y of age (female/male) with tumours of the suprasellar or pineal areas were followed in our clinic to study the incidence of precocious puberty. In addition, type of central lesion, clinical characteristics and gonadotropic secretion were studied in order to elucidate the different mechanisms of gonadal activation. A control group of 21 patients with idiopathic precocious puberty and a control group of 10 age‐matched patients with suprasellar tumours without precocious puberty were also studied. Precocious puberty associated with organic central lesions was found at diagnosis in 30 patients (26%), in 9 out of 48 patients with glial cell tumours (18.7%), 6 out of 9 patients with gem cell tumours (66.6%), 11 out of 11 patients with hypothalamic hamartomas (100%) and in 4 out of 4 patients with subarachnoid cysts or arachnoidocele (100%). Precocious puberty was not found in any of 36 patients with craniopharyngioma. With the exception of one patient with pineal germinoma, all lesions were localized to the suprasellar area. In all patients with hypothalamic hamartoma, precocious puberty was diagnosed before 4 y of age, while in most patients with the other lesions, it was diagnosed after this age. Height SDS, weight increase and advancement of bone age were similar in both idiopathic and organic central precocious puberty. Maximal LH responses to GnRH in idiopathic and organic central precocious puberty were similar except for germ cell tumours. Patients with suprasellar tumours without precocious puberty had lower maximal LH (but not FSH) responses to GnRH, with the exception of germ cell tumours. In the latter, elevation of serum β‐hCG indicates that this gonadotropin was responsible for gonadal stimulation. In hypothalamic hamartomas, the prepubertal hiatus in the activity of the GnRH pulse generator was absent. The mechanism of this failure in the inactivation of GnRH is unknown. Data suggest that in glial cell tumours and in subarachnoid cysts, an unknown factor, probably secreted by the tumours, advances the tempo of GnRH maturation. Therefore, the aetiology of organic central precocious puberty is multiple and is directly related to location and type of lesion. Conclusion: This clinical information suggests that the onset of puberty is not the result of the disruption of a putative pulse generator inhibitory influence but the consequence of secretion of stimulatory substances by the lesions.

Objective: Inhibin B is a secretory product of Sertoli cells of the human testis. It has been reported that serum levels of inhibin B in infant boys, peaking at 3 months of age, exceed levels in adult men. The aim of this study was to evaluate inhibin B secretion in primary prepubertal mixed testicular cell cultures, prepared from testes collected at necropsy. Design and Methods: Cell cultures were divided into three age groups on the basis of differences in testicular histology: group 1 (n ¼ 7), 1-to 10-day-old newborns, group 2 (n ¼ 7), 1-to 9-month-old infants, and group 3 (n ¼ 8), 12-to 84-month-old children. Cells were maintained in culture for 6 days, harvested and counted. In some samples, during the last 4 days, cells were stimulated with 10 ng/ml highly purified human (h) LH (n ¼ 9), 2 ng/ml recombinant human (rh) FSH (n ¼ 9) or 50 ng/ml rhGH (n ¼ 4). On day 6, the secretion of inhibin B and testosterone into the medium was estimated in triplicate. Inhibin B was determined by ELISA and testosterone by RIA. Results: Median (range) inhibin B secretion was 465 (225-1007), 275 (107-298), and 58 (15-184) pg/million cells.24 h in groups 1, 2 and 3 respectively. A logarithmic transformation of these values was performed to normalize data. Mean Ϯ S.D. of transformed inhibin B secretion in group 1 was significantly higher than in group 2 or 3 (P < 0:005) and the values for groups 1 and 2 were significantly higher than that for group 3 (P < 0:005). No significant correlation between testosterone and inhibin B secretion into the medium was found when the 22 culture samples were analyzed as a whole. Inhibin B secretion was significantly increased after stimulation with highly purified hLH, rhFSH and rhGH (P < 0:05) and a significant positive correlation between inhibin B and testosterone was found under both hLH and rhFSH stimulation. Conclusions: It is concluded that cells collected from newborns have the highest capacity to secrete inhibin B in vitro, and that this capacity decreases with age during the first years of life. Since no data are available on serum inhibin levels in newborns, it is possible that concentrations at 3 months of age do not represent a post-natal peak but a declining level of high newborn values. As expected, FSH stimulated inhibin B secretion in culture. LH stimulation was probably mediated by paracrine factors secreted by interstitial cells. Finally, our results add new evidence of the involvement of GH in testicular maturation.

Tumor oncotypes, initial symptoms and endocrine disturbances before and/or 1 month after surgery were studied in 66 patients with prepubertal and pubertal ages having suprasellar or pineal intracranial tumors. Neoplasms found in patients of prepubertal age were: 15 craniopharyngiomas (CRA), 24 neuroepithelial-cell-derived tumors (NEC), 5 germ cell tumors (GERM) and 4 other lesions (OTHER). In patients of pubertal age, there were 7 CRA, 7 pituitary tumors (PIT), 2 NEC, 1 GERM and 1 OTHER. Approximately 90% of patients had visual abnormalities as one of the initial signs and symptoms, while 59% had increased intracranial pressure. Short stature was observed in only 10% of patients. Before surgery, somatotropic function was found to be deficient (by 2 pharmacological tests) in 90-100% of patients with CRA, PIT or GERM and in 40% of patients with NEC. Overt hypothyroidism was found in 5-25% of CRA, NEC or GERM but in 40% of PIT. Abnormal TSH responses to TRH were observed in 64% of CRA and in 29% of NEC. Low basal serum cortisol was found in 21 or 6% of patients with CRA or NEC, but in 100 or 60% of patients with PIT or GERM, respectively. Diabetes insipidus was diagnosed in 13.6% of all patients. Surgery produced few additional disturbances in endocrine function, except for the incidence of diabetes insipidus which was doubled. Gonadotropic deficiency was found in most patients of pubertal age with CRA and PIT. They were readily differentiated by the high prolactin or growth hormone (GH) levels of the latter. This study shows that: (1) CRA and NEC in the prepubertal age group, and CRA and PIT in the pubertal age group were the most frequent tumor oncotypes found; (2) visual abnormalities are the most frequent initial signs; (3) endocrine disturbances are highly frequent before surgery, while surgical intervention had little effect in increasing endocrine morbidity; (4) NEC, even though producing less endocrine dysfunctions than other tumor types, are an important etiology of endocrine sequelae because of their high relative frequency in children with prepubertal age.

Serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) morning levels were determined in 327 normal prepubertal and early pubertal children of both sexes, utilizing a highly sensitive and specific microparticle enzyme immunoassay. Female (F) and male (M) prepubertal (Tanner's stage I) subjects were divided into 4 age groups: less than 3 months (F1, M1), 3 to 12 months (F2, M2) 12 to 24 months (F3, M3) and older than 24 months (F4 and M4). F pubertal subjects were classified in Tanner's stage breast II (F5) and III F6), while M pubertal subjects belonged to Tanner's stage genitalia II (M5). Serum LH levels were relatively low in prepubertal girls and showed a significant increment in group F6. By contrast, serum LH levels were relatively high in M1 and M2, decreased to levels similar to F in M3 and M4, and increased again at puberty in M5. Serum FSH levels were relatively high in girls of all prepubertal groups, even though they decrease significantly in M4. An increase was detected in pubertal group M6. All M prepubertal groups had significantly lower FSH levels than F prepubertal groups. The high serum LH of boys during the first year of life is probably a consequence of an activation of the hypothalamic GnRH pulse generator that is not apparent in girls. On the other hand, the high serum FSH of prepubertal girls is probably a consequence of a weak restraint influence of the prepubertal ovary on pituitary FSH secretion. This sexual dimorphism in gonadotropin secretion regulates, in a sex-specific fashion, prepubertal gonadal function in the two sexes.