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Abstract. An evaluation of the usefulness of determining the decrease in serum sex hormone-binding globulin after exogenous testosterone was studied in 55 prepubertal patients with ambiguous external genitalia or micropenis. The biochemical response (androgen sensitivity test) was compared with the clinical response as judged by signs of androgen stimulation of external genitalia. Patients were divided in two groups according to age. Group I, 11 patients younger than 3 months and Group II, 44 patients older than 3 months. Only in 54% of Group I was there a correlation between the androgen sensitivity test and the clinical response to androgens in either a positive (4 patients) or negative sense (2 patients). On the other hand, the androgen sensitivity test and the clinical response to androgens correlated in 91% of the patients of Group II in either a positive (35 patients) or negative sense (5 patients). Two of the 4 patients with lacking correlation had a negative androgen sensitivity test and micropenis secondary to pituitary deficiency. It is concluded that in prepubertal patients older than 3 months with abnormalities of sex differentiation, the androgen sensitivity test and the clinical response to androgens are useful for evaluating androgen sensitivity. The clinical response to androgens is useful in early life when a positive response is found.

It has been reported that growth hormone modulates serum levels of insulin-like growth factor I (IGF-I) positively and serum levels of sex-hormone-binding globulin (SHBG) negatively. We have measured IGF-I and SHBG concentrations in 24 prepubertal patients with growth hormone deficiency. Twelve of these patients had had intracranial tumors removed (organic growth hormone deficiency) and 12 had growth hormone deficiency of unknown etiology (idiopathic). Fifty-two prepubertal control subjects, admitted for elective surgery, were also studied. All prepubertal patients were divided into two age groups: older and younger than 7 years of age. In both groups there were patients with multiple pituitary deficiencies on hydrocortisone and/or levothyroxine sodium replacement therapy. In the age group younger than 7 years, serum IGF-I was not significantly different between organic and idiopathic growth hormone deficiency (0.28±0.21 versus 0.062±0.071 mU/l) but serum SHBG levels were different (74.6±33.5 versus 173±59 nmol/l, p<0.05). These values were not significantly different from controls (0.47±0.25 mU/l and 132±47 nmol/l, respectively). In the age group older than 7 years, there was no significant difference between organic and idiopathic growth hormone deficiency in serum IGF-I (0.33±0.17 versus 0.16±0.11 mU/l) or serum SHBG (113±72 versus 108±17 nmol/l). These values were significantly different from controls (1.04±0.36 mU/l and 68.7±31.7 nmol/l, p<0.05, respectively). It is concluded that serum IGF-I and serum SHBG are regulated by growth hormone in late puberty. In early prepuberty, however, the effect of growth hormone on these two serum parameters seems to be weak. This phenomenon could be related to an increase in the sensitivity of the cellular response to the biological effects of growth hormone with age.

The aim of the present work was to develop a method for maintaining prepubertal human testicular cells in culture. Seven pairs of testes of boys who died of causes unrelated to endocrine or metabolic diseases were obtained at necropsy. Histology of the testes was normal. Testes were digested with collagenase and dispersed cells were seeded in multi-well dishes in the presence of 5% bovine fetal serum. After the first day, cells were cultured for five days in serum-free medium in the presence or absence of 918 pmol/l insulin. At the end of culture, microscopic examination showed healthy looking cells with characteristics compatible with pre-Sertoli cells; peritubular cells were identified by immunocytochemistry. In the presence of insulin, cells were able to secrete either testosterone or estradiol into the medium, as well as to reveal aromatase activity. In order to study the effect of the time elapsed between death and beginning of cultures, steroidogenic activity was related to this post mortem time. It was found that, in the presence of insulin, cells obtained from testes with less than 24 h of post mortem time secreted testosterone (64±7.2 pmol/10⁶ cells·24 h, mean±sd) while cells obtained from testes with more than 24 h of post mortem time did not secrete testosterone. With long post mortem times, aromatase activity under insulin increased from non-detectable to 35 pmol/10⁶ cells·24 h. Time course studies showed that cells with capacity to secrete testosterone increase this secretion gradually up to day 10 of culture, while those with detectable aromatase activity showed increments in this activity during the first week of culture. It is concluded that it is possible to maintain cultures of prepubertal human testicular cells obtained at necropsy. In order to maintain testosterone secretion capacity, the time between death and initiation of culture should not exceed 24 h.