Differences in serum insulin-like growth factor I and sex-hormone-binding globulin levels between late and early prepuberty in patients with idiopathic and organic growth hormone deficiency

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).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of serum total thyroxine and triiodothyronine and their serum fractions in nonthyroidal illness secondary to congenital heart disease. Studies before and after surgery

Serum thyroid hormones, serum thyroxine-binding proteins and serum thyroid hormone fractions have been measured in children with congenital heart disease before and after open cardiac surgery. Twenty prepubertal patients, mean (+/- SD) age 3.6 +/- 3.7 yr, were studied before, immediately after, and 24 and 48 h after surgery. A control group of 6 normal prepubertal children was also studied in basal conditions. Serum TSH was normal in all samples collected. Significantly low mean levels of serum TBG (261 +/- 57 vs 456 +/- 71 nmol/L in normals), serum TBPA (2692 +/- 1119 vs 5999 +/- 2226 nmol/L), serum TBG-bound T4, serum TBPA-bound T4, serum TT3, serum TBG-bound T3 and free T3 were found before cardiac surgery in the patients. While serum binding proteins did not change after surgery, significant decrements in serum TT4, serum TBG-bound T4, serum TT3, serum TBG-bound T3, serum albumin-bound T3 and free T3 were observed after surgery. Free T4 and albumin-bound T4 remained normal. Our study shows that many features of nonthyroidal illness were present in our patients before surgery. In this context, the stress of surgery induced further alterations in several parameters of thyroid metabolism. It is concluded that the changes occurring in this model of chronic, as well as acute, nonthyroidal illness reflect adaptative changes, rather than altered thyroid function, as shown by normal serum free T4, serum albumin-bound T4 and serum TSH.

Hypothalamic-pituitary-gonadal function in prepubertal boys and girls with chronic renal failure

Hypothalamic-pituitary-gonadal function was evaluated in 24 prepubertal children with chronic renal failure (CRF). Among the 17 boys, 5 were receiving conservative treatment and four long-term dialysis. Another eight boys were studied 6 months to 3.3 years after renal transplantation; their ages ranged from 5 years 8 months to 15 1/2 years. Among the girls, two patients were receiving conservative treatment and five long-term dialysis; their ages ranged from 3 1/2 years to 11 years 2 months. In boys with CRF, but not in those after transplantation, mean serum follicle-stimulating hormone 60 minutes after administration of gonadotropin releasing hormone (GnRH) was lower than in 18 control prepubertal boys (mean +/- SD: 2.53 +/- 1.34 vs 6.25 +/- 2.84 IU/L, respectively; p < 0.01). Testosterone steroidogenic capacity after 1 week of stimulation with human chorionic gonadotropin and androgen sensitivity (percentage of decrease of serum sex hormone-binding globulin 1 week after intramuscular administration of testosterone enanthate) were normal. In girls, no difference between those with CRF and a control group of 19 girls was found after intravenous administration of GnRH. However, after intramuscular administration of GnRH agonist, serum follicle-stimulating hormone concentration was lower in girls with CRF than in control girls (p < 0.02); six of seven control girls had an increase of serum estradiol to more than 55 pmol/L, whereas three of seven girls with CRF had no response, and serum follicle-stimulating hormone failed to increase after GnRH agonist therapy in two of these patients. We conclude that hypothalamic-pituitary function is not normal in some prepubertal boys and girls with CRF, particularly in those with low serum albumin concentrations. On the other hand, testicular and ovarian steroidogenic capacity is not impaired, and the biologic response to androgens in boys is preserved.

High serum sex hormone-binding globulin (SHBG) in premature thelarche

OBJECTIVE

We determined serum sex hormone-binding globulin (SHBG), serum dehydroepiandrosterone sulphate, serum oestradiol and serum testosterone and its fractions in girls with premature thelarche.

DESIGN

Blood was drawn from girls with recently diagnosed (3-12 weeks) premature thelarche. Serum was kept frozen for at least one year before hormonal determination to exclude precocious puberty by clinical evaluation.

PATIENTS

Seventeen girls with premature thelarche aged 0.83-7.16 years were studied, and compared with a group of 22 normal prepubertal girls.

MEASUREMENTS

SHBG was measured by saturation analysis and serum dehydroepiandrosterone sulphate, serum total oestradiol and serum total testosterone were determined by radioimmunoassay. Non-SHBG-bound testosterone and free testosterone were calculated from an equation derived from the law of mass action.

RESULTS

Median serum SHBG in premature thelarche was 137 nmol/l (range 64-221), significantly higher than in normal controls, 93.7 (32-172) (P < 0.05) non-parametric test of medians. Serum SHBG decreased significantly with age in controls but not in premature thelarche. No difference was found in serum dehydroepiandrosterone sulphate. Median serum total testosterone (0.34 nmol/l, 0.17-0.97), median serum non-SHBG-bound testosterone (0.04 nmol/l, 0.02-0.10) and median free testosterone (2.2 pmol/l, 1.0-4.5) were significantly lower in premature thelarche than in control (P < 0.001).

CONCLUSIONS

Serum SHBG is high and bioavailable T is low in girls with premature thelarche. This might alter the oestrogen/androgen ratio in the breast.

Primary culture of prepubertal human testicular cells isolated from testes collected at necropsy

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/10(6) 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/10(6) 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.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocrine disorders in 66 suprasellar and pineal tumors of patients with prepubertal and pubertal ages

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.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum sex hormone-binding globulin and serum nonsex hormone-binding globulin-bound testosterone fractions in prepubertal boys with chronic renal failure

We had previously reported that serum sex hormone binding-globulin (SHBG) decreases and serum non-SHBG-bound testosterone (T) and free T increase significantly from infancy to late prepuberty in normal prepubertal children of both sexes. We had also shown an age-related delay in these changes in hypopituitary boys, which was reversed by GH treatment. Stunted growth and delayed puberty are conspicuous features of chronic renal failure (CRF). As another model of delay of growth and development, serum SHBG and serum T fractions were determined in 13 boys with CRF on chronic dialysis. In CRF, mean serum SHBG was significantly higher (99.1 +/- 68.9 nmol/L; P less than 0.05) than in 31 control (C) children of similar ages (66.2 +/- 34.9 nmol/L), while serum non-SHBG-bound T and free T were significantly lower (0.16 +/- 0.12 in CRF vs. 0.24 +/- 0.12 in C and 0.010 +/- 0.005 in CRF vs. 0.016 +/- 0.01 in C, respectively). On the other hand, serum total T (1.31 +/- 0.88 in CRF vs. 1.08 +/- 0.56 in C) and serum insulin-like growth factor-I (IGF-I; 1.06 +/- 0.74 in CRF vs. 1.35 +/- 1.70 in C) were not significantly different. A significant negative correlation between serum SHBG and chronological age as well as a significant positive correlation between serum non-SHBG-bound T and chronological age were found. For a given age, serum SHBG was higher, while serum non-SHBG-bound T was lower in patients with CRF (by analysis of covariance, P less than 0.01). It is postulated that, as has been proposed for hypopituitary boys, this delayed increment in serum T fractions could be responsible for the delay in the onset of puberty reported in CRF. It is known that GH decreases serum SHBG, acting on hepatic cells either directly or through the action of IGF-I. Since it has been suggested that patients with CRF have peripheral resistance to GH or IGF-I, the high levels of SHBG that we have detected in prepubertal boys with CRF could be taken as an additional evidence of this biological resistance.

Glucocorticoids and adrenal androgens in children with end stage renal disease

We studied the effects of chronic renal failure on the pituitary-cortisol axis and adrenal androgen function in 26 patients (16 male and 10 female), aged 6.5 to 22.5 years (mean 14.5). Ten patients were prepubertal, 8 pubertal, and 8 post-pubertal. All of them were on chronic hemodialysis. Pubic hair development was delayed in 56% of the patients. Serum cortisol was increased in 15 out of the 26 patients. Serum delta 4-androstenedione was high in 11 out of 15 patients in Tanner's stage I or II and in 1 out of 11 patients in Tanner's stage III, IV or V (p less than 0.01). Serum cortisol was elevated in 10 out of 12 patients with high serum delta 4-androstenedione and in only 5 out of 14 with normal delta 4-androstenedione (p less than 0.02). Serum dehydroepiandrosterone sulphate was normal in 22 patients and elevated in 4 males. There was a significant inverse correlation between bone age and serum cortisol (r: -0.59; p less than 0.005) and a significant positive correlation between bone age and serum dehydroepiandrosterone sulphate (r: 0.45 p less than 0.01). Serum ACTH was normal. A reduction by 50% in cortisol and 78% in dehydroepiandrosterone sulphate was found after dexamethasone suppression, but delta 4-androstenedione did not suppress after dexamethasone. After ACTH stimulation test cortisol increased by 50% and delta 4-androstenedione by 80%.

CONCLUSIONS

The increased levels of cortisol and delta 4-androstenedione with partial resistance to dexamethasone suggest that these patients have a hypothalamic-pituitary dysfunction similar to that found in Cushing's disease or in chronic stress. The difference in the responses of delta 4-androstenedione and dehydroepiandrosterone sulphate observed is consistent with the existence of different mechanisms of control for these two steroids.

Hormonal and paracrine regulation of gamma-glutamyl transpeptidase in rat Sertoli cells

The effects of follicle-stimulating hormone (FSH) and testosterone on Sertoli cell gamma-glutamyl transpeptidase (gamma-GTP) activity have been studied in vitro. Addition of FSH to Sertoli cell cultures for 5 days induced stimulation of gamma-GTP activity. No testosterone effect was observed alone or in combination with different doses of FSH. Time course studies for a supramaximal dose of FSH showed that enzyme induction could be achieved after a 48 h stimulation. Furthermore, a gradual stimulation of gamma-GTP activity in response to increasing numbers of germinal cells (GC) added in coculture, was observed. Stimulation was also demonstrated with germinal cell-conditioned medium (GCCM). Stimulatory effects of GC and GCCM were additive with those of FSH, suggesting that different mechanisms were involved.

Lack of correlation of serum estradiol with growth velocity during male pubertal growth

The adolescent growth spurt in boys is under hormonal control. It is accepted that androgens and growth hormone contribute to male pubertal growth, but the role of estrogens is uncertain even though low-dose estradiol administration stimulates growth in prepubertal boys. In the present work, the correlation of serum testosterone and serum estradiol with growth velocity was studied in 16 pubertal normal boys. The study included correlations of growth velocity with serum nonsex hormone-binding globulin-bound testosterone and with serum nonsex hormone-binding globulin-bound estradiol, which are parameters of serum bioavailable sex hormones. A statistically significant positive correlation was found between serum testosterone and growth velocity but not between serum estradiol and growth velocity. These findings are against the hypothesis that estrogens play a growth promoting role during male puberty.

Thyroid dysfunction in Hodgkin's disease

Radiotherapy to the neck and/or polychemotherapy late effects on the thyroid were investigated in 51 patients (34 males and 17 females) with Hodgkin's disease. Except for two untreated, recently diagnosed patients, all were studied after 1 to 105 months (median, 27.5 months) of completion of polychemotherapy. Age ranged from 6.2 to 36.6 years (median, 13.6 years). Patients were divided according to treatment into four groups: (A) patients treated with CVPP (cyclophosphamide, vinblastine, procarbazine, and prednisone); (B) 22 patients treated with CVPP plus radiotherapy (median radiation dose to the thyroid, 3000 cGy); (C) seven patients with ACOP/BVP (adriamycin, cyclophosphamide, vincristine, prednisone, bleomycin, vinblastine, procarbazine); and (D) seven patients treated with different polychemotherapy protocols, four of whom also received radiotherapy. Elevated basal and/or post-TRH, -TSH levels were found in the following: Group A: two of 12 patients (17%); Group B: 11 of 22 (50%); Group C: four of seven (57%); and Group D: two of seven (28%). Positive antimicrosomal thyroid antibody titers (AM Ab) were found in the following: Group A: three of 12 patients (25%); Group B: six of 21 (28%), Group C: two of seven (28%); and Group D: one of six (17%). Of 46 patients studied, 12 (26%) had positive AM Ab; 37 of 46 patients were younger than 20 years of age, 11 (30%) of whom had positive AM Ab versus 4% in the normal population (P less than 0.001). Two recently diagnosed, untreated patients had either high TSH response to TRH or positive AM Ab. In conclusion, higher frequency of thyroid dysfunction was observed in patients receiving radiotherapy (50% versus 27%). Prevalence of positive AM Ab, apparently unrelated to therapy, was higher in young patients than in the normal population. A predisposition to autoimmune thyroid disease seems to be present in these patients, but it is not possible to discern how lymphoma and thyroiditis are interrelated.

Progressive increase in nonsex hormone-binding globulin-bound testosterone and estradiol from infancy to late prepuberty in girls

We previously reported that serum sex hormone-binding globulin (SHBG) decreases and serum non-SHBG-bound testosterone (T) increases with age in normal prepubertal boys from infancy to late prepuberty. In this study we measured serum SHBG, T, estradiol (E2), and dehydroepiandrosterone sulfate (DS), and we calculated serum non-SHBG-bound T and E2 and free T and E2 in 22 normal prepubertal girls, aged 1-9.4 yr. The girls were divided into 3 groups of different ages: group A, 1.7 +/- 1.0 (mean +/- SE) yr; group B, 4.6 +/- 0.8 yr; and group C, 7.3 +/- 0.8 yr. In group C, mean serum SHBG level was lower, and serum T, non-SHBG-bound T, free T, DS, total E2, non-SHBG-bound E2, and free E2 were higher than in group A or B. Furthermore, a negative correlation was found between serum SHBG and age [y(nmol/L) = 144 - 9.07 x (yr); r = 0.57; P less than 0.001], while positive correlations were found between non-SHBG-bound T and age [y(nmol/L = 0.043 + 0.023 x (yr); r = 0.68; P less than 0.001], non-SHBG-bound E2 and age [y(pmol/L) = 0.69 + 2.82 x (yr); r = 0.6; P less than 0.001], and DS and age [y(nmol/L) = 25.2 + 63.8 x (yr); r = 0.59, P less than 0.001]. In a group of 19 normal age-matched prepubertal boys, we also found a significant correlation between non-SHBG-bound E2 and age. Since non-SHBG-bound sex hormone levels are good indicators of tissue available sex hormones, we conclude that in prepubertal girls, there is a progressive increase in the exposure of peripheral tissues to T and E2 with advancing age. Since sex hormones enhance tissue maturation, these increments might play a role in the somatic and psychic development of girls before the onset of the clinical signs of puberty.

Hormonal regulation of rat testicular gamma-glutamyl-transpeptidase "in vivo" and "in vitro"

The hormonal regulation of gamma-glutamyl transpeptidase (gamma-GTP), an enzyme marker of Sertoli cells, was studied in immature rats that received 50 micrograms/day of testosterone propionate (TP) during 6 days to suppress pituitary LH and FSH. Suppression of LH was monitored indirectly by the determination of intratesticular levels of testosterone and suppression of FSH by radioimmunoassay of serum FSH. Enzyme activity in the testis decreased in parallel to intratesticular testosterone suppression, and it did recover up to control values when animals received 500 micrograms/day of TP, a dose that was able to maintain intratesticular testosterone at normal levels. beta-glucuronidase, another enzyme marker of Sertoli cells, was not affected by these treatments. A significant decrease in gamma-GTP was detected 24h after significant suppression of intratesticular testosterone and it returned to control levels 2 days after increasing the dose of TP to 500 micrograms/day. Administration of FSH to rats with depletion of intratesticular testosterone was able to maintain testicular gamma-GTP at control levels. An stimulatory action of FSH could also be demonstrated in primary Sertoli cell cultures. It is concluded that testicular gamma-GTP is under the regulation of both androgens and FSH while beta-glucuronidase is not. Eventhough the function of gamma-GTP in the testis is not known, the key role that it plays in other tissues suggests that it might be important in the regulation of Sertoli cell-germ cell interactions.

High serum sex hormone-binding globulin (SHBG) and low serum non-SHBG-bound testosterone in boys with idiopathic hypopituitarism: effect of recombinant human growth hormone treatment

We measured serum sex hormone-binding globulin (SHBG), total testosterone (T), non-SHBG-bound T, albumin-bound T, free T, and SHBG-bound T in 19 prepubertal boys with hypopituitarism. Serum SHBG decreased with age with a slope similar to that in 91 normal prepubertal boys at higher level, and therefore, it reached similar values at a later age. Serum SHBG was significantly higher in hypopituitary prepubertal boys [mean, 123 +/- 12 (+/- SE) nmol/L] than in normal prepubertal boys (76 +/- 4; P less than 0.001) despite the fact that their mean age was also higher (10.0 +/- 4 vs. 7.1 +/- 4.1 yr; P less than 0.001). In 4 boys with isolated hypogonadotropic hypogonadism (Kallman's syndrome), aged 15.6 +/- 1.5 yr, serum SHBG was 21 +/- 14 nmol/L, a value below the 95% confidence limit of the regression line in GH-deficient boys. The affinity constants of association of the SHBG-DHT complex were similar in hypopituitary and normal boys. Eleven of the 19 hypopituitary boys (mean chronological age, 8.3 +/- 2.5 yr; mean bone age, 4.1 +/- 2.1 yr) were treated with recombinant hGH (0.5 U/kg BW.week) for 1 yr. Their mean serum SHBG level before treatment was 154 +/- 14 nmol/L, and it decreased gradually to 106 +/- 5 nmol/L (P less than 0.01) after 12 months of treatment. The tendency toward normalization of serum SHBG during treatment suggested that GH deficiency was responsible for the high serum SHBG levels. Serum SHBG correlated negatively with age in both treated hypopituitary and normal boys, but the slope of the regression line was significantly steeper in treated hypopituitary boys (P less than 0.01). On the other hand, the mean serum non-SHBG-bound T level was 0.10 +/- 0.02 (+/- SE) nmol/L in hypopituitary boys, significantly lower than that in normal boys (0.21 +/- 0.02 nmol/L; P less than 0.02). Since serum total T concentrations were similar in the two groups, the higher serum SHBG concentration resulted in lower serum bioavailable T levels in the hypopituitary boys. These changes might explain the poor response to T treatment reported in GH-deficient patients. The lower serum non-SHBG-bound T concentrations in the GH-deficient boys suggest there may be delayed exposure of central nervous system structures to increased levels of sex hormones, which, in turn, may slow body maturation. This mechanism might play a role in the delay of puberty that occurs in patients with isolated GH deficiency.

Validity of the calculation of non-sex hormone-binding globulin-bound estradiol from total testosterone, total estradiol and sex hormone-binding globulin concentrations in human serum

Recent evidences indicate that biologically available serum testosterone (T) and estradiol (E2) include not only the free fractions but also most of the albumin-bound fractions. These two serum T or E2 fractions constitute most of non-sex hormone-binding globulin (SHBG)-bound T or E2, respectively. It has been reported that the estimation of serum non-SHBG-bound T gives identical results when it is assayed experimentally or when it is calculated by a formula derived from the law of mass action assuming two binding systems (T-SHBG and T-albumin). In the present work, we have compared the results of the experimental measurement of non-SHBG-bound E2 with the calculated value derived by an equation based on the law of mass action considering four binding systems (E2-SHBG, T-SHBG, E2-albumin, T-albumin). It was found that the two estimations of non-SHBG-bound E2 correlated closely in normal men (r = 0.80), normal women (r = 0.90) and hirsute women (r = 0.98). When compared with a more complex calculation which includes 21 steroids and 3 binding proteins results also agreed closely. Values for the different T and E2 fractions in these groups of subjects are given. These calculations could be used, not only for clinical research, but also in clinical practice as an useful tool for evaluation of the sex hormone status of patients.

Hormonal profile in pubertal females with chronic renal failure: before and under haemodialysis and after renal transplantation

The effects of chronic renal failure on the hypothalamic-pituitary-ovarian axis in 25 girls, aged 9.1 to 20.9 years (mean 13.8) were studied. Twelve patients on conservative treatment (group A) had serum creatinine values between 176.8 and 1502.8 mumol/l; 9 patients were on haemodialysis (group B); and 12 patients had received a renal transplant (group C). Tanner stage of breast development was delayed relative to chronological age in 5 out of 18 patients. Serum oestradiol was normal or low when related to pubertal stages in all groups. Serum LH was elevated in group A and B patients, but normal in group C patients. Serum FSH was elevated in 6 out of the 21 patients in group A plus B, and in 2 out of the 12 patients in group C. Serum PRL was elevated in 12/12, 6/8, and 4/11 patients in group A, B, and C respectively. After GnRH administration to 4 patients in group A, 3 showed delayed or absent gonadotropin response; all 4 patients studied in group C showed normal gonadotropin response. The data indicate a decreased E2 secretion, abnormal gonadotropin and PRL levels and a blunted gonadotropin response to GnRH in girls with chronic renal failure. These results seem to indicate an alteration of the hypothalamic-pituitary unit that can be reversed after successful renal transplantation.

Progressive increase in non-sex-hormone-binding globulin-bound testosterone from infancy to late prepuberty in boys

Recent evidence suggests that human albumin-bound testosterone (HSA-bound T), the major constituent of nonsex hormone-binding globulin-bound T (non-SHBG-bound T), is biologically important. To examine the potential exposure of peripheral tissues to T in normal prepubertal boys, we determined the distribution of serum T into SHBG-bound, HSA-bound, non-SHBG-bound, and free fractions in 80 normal males, aged 0.5-14 yr, all at Tanner stage I of sexual development. A model assuming equilibrium between free T and T bound to 2-binding proteins (HSA and SHBG) was used. A computer program, using as constants the SHBG-T and HSA-T affinity constants and the serum HSA concentration and as variables the serum SHBG and total T concentrations, was used to calculate SHBG-bound T, HSA-bound T, non-SHBG-bound T, and free T. Serum total T increased 2.6-fold from 0.5 to 14 yr, whereas non-SHBG-bound T, HSA-bound T, and free T increased 8- to 9-fold during the same period. On the other hand, SHBG-bound T increased only 1.9-fold. Expressed as a function of serum total T, non-SHBG-bound T increased from 6.6% to 30.4%, the relative increment being greater for HSA-bound than for free T. We conclude that with advancing age, there is a progressive increase in the exposure of all tissues to T in normal prepubertal boys. At the level of the central nervous system, this increase in serum bioavailable T could induce maturative changes in brain cells that result in the onset of puberty in normal boys.

Evaluation of gonadal function following long-term treatment for acute lymphoblastic leukemia in girls

Twenty-four girls were studied following long-term treatment (mean: 50 months) for acute lymphoblastic leukemia; 14 were prepubertal and 10 pubertal. Follow-up during endocrine studies ranged from 2 months to 6.7 years (mean: 2.3 years). Five of 14 prepubertal patients started clinical pubertal development at a normal age and were reevaluated during puberty, increasing the pubertal group to 15 patients. Thirteen of 15 pubertal patients had received cranial radiotherapy. Ten of 15 pubertal patients started menses during the endocrine study. Although age of menarche was normal, in nine patients it was below the normal mean. Except for the remaining patient, all had received cranial cobalt therapy. In 6 of 19 patients bone age was significantly accelerated. Serum gonadotrophin response to LH-RH was normal in 13 prepubertal patients and in 10 pubertal patients. In 3 of 10 pubertal patients follicle-stimulating hormone (FSH) values were temporarily elevated. Only one pubertal patient had oligoamenorrhea. Five patients were studied by measuring serum progesterone on days 19-22 of the cycle to determine corpus luteum function. Three of them showed progesterone levels compatible with adequate corpus luteum function (6, 19, and 12 ng/ml, respectively) and two presented low progesterone levels (2 ng/ml), probably because of their short gynecological age (0.24 and 0.3 years, respectively). This study suggests that neither the disease nor the long-term antileukemia therapy seems to injure gonadal function in girls. A tendency to early sexual development was observed, which may be related to cranial cobalt therapy.

Changes in serum sex hormone-binding globulin and in serum non-sex hormone-binding globulin-bound testosterone during prepuberty in boys

Much evidence suggests that sex hormone-binding globulin (SHBG) influences the delivery of sex steroids to cells, probably by playing an important role in the distribution of serum sex hormones between SHBG-bound, albumin (HSA)-bound and free fractions. Recent evidence also suggests that HSA-bound testosterone (T), the major constituent of non-sex hormone-binding globulin-bound T, is biologically important. To examine the potential exposure of peripheral tissues to T during prepubertal years, the serum concentration of SHBG as well as the distribution of serum T in SHBG-bound, HSA-bound, free and non-SHBG-bound fractions was studied in 80 normal boys aged 0.5-14 yr, all at Tanner's stage G1 of sexual development. A gradual decrease in serum SHBG as a function of age was found without significant changes in the Ka of SHBG-dihydrotestosterone association. While regression analysis of serum total T vs age showed a 2.6-fold increase from 0.5 to 14 yr of age, those of non-SHBG-found, HSA-bound and free T vs age showed 8- to 9-fold increases during the same period. On the other hand, SHBG-bound T had only a 1.9-fold increase. Expressed as a function of serum total T, non-SHBG-bound T increased from 6.6 to 30.4%, the relative increment being greater for HSA-bound T than for free T. It is concluded that, with advancing age, there is a progressive increase in the T exposure of all tissues in normal prepubertal boys. It is speculated that, at the level of the central nervous system, this increase in serum bioavailable T could induce maturative changes in brain cells that result in the onset of puberty in normal boys.

Paracrine regulation of testicular function

Data from several experimental approaches have been reviewed and the findings clearly indicate the existence of multiple interactions between testicular cells and the potential role of these interactions in the paracrine control of testicular functions. Both testicular interstitial fluid and spent media from cultured Sertoli cells had an acute steroidogenic effect on Leydig cells, and this effect is not species specific. The secretion of this steroidogenic factor(s), which is probably a protein, is enhanced by previous FSH treatment of Sertoli cells. Coculture for 2-3 days of pig Leydig cells with homologous or heterologous Sertoli cells enhances Leydig cell specific functions (hCG receptor number and hCG responsiveness) and induces Leydig cell hypertrophy. A similar but less pronounced trophic effect is seen when Leydig cells are cultured with spent media from Sertoli cells cultured in the presence of FSH and high concentrations of insulin, but the spent media from Sertoli cells cultured in the absence of these two hormones inhibits Leydig cell specific functions. Somatomedin-C might play an important role in the positive trophic effect of Sertoli cells on Leydig cells, since this peptide is secreted by Sertoli cells and it has trophic effects on the specific function of Leydig cells. Moreover, Sertoli cells, probably through a diffusible factor and cell-to-cell contacts, control the multiplication, meiotic reduction and maturation of germ cells. In turn, the activity of Sertoli cells is modulated by the stage of neighbouring germ cells. Thus, if a normal Sertoli cell function (which depends not only on FSH but also on Leydig and myoid cell secretory products) is an absolute requirement for germ cell multiplication and maturation, these cells, in turn, cyclically regulate Sertoli cell function and through these cells the size and probably the function of Leydig cells.

Inhibition of RNA and DNA synthesis in Sertoli cells by co-culture with spermatogenic cells

Sertoli cell monolayers were prepared from 30-day-old rat testes and cultured for 7 days to eliminate contaminant germ cells. Some of these monolayers were co-cultured with a spermatogenic cell preparation enriched in pachytene spermatocytes and round spermatids (fraction 3 from a Percoll gradient), isolated from 30-day-old rat testes. After co-culture for 4 to 48 h, germ cells were removed. RNA synthetic activity in rat Sertoli cell cultures alone was 216,800 +/- 66,480 dpm [3H]uridine.2h-1 X 10(6) cells-1 (mean +/- SD) compared to 98,390 +/- 23,595 in rat Sertoli cells which had been co-cultured with germ cells of fraction 3 for 24 h (P less than 0.01). By contrast, RNA synthesis in Sertoli cell monolayers prepared from immature pigs were unaffected by co-culture with rat germ cells. A similar inhibitory effect of germ cells was observed in rat Sertoli cells stimulated with FSH or testosterone. Culture medium, conditioned by 20 h culture of a fresh preparation of rat spermatogenic cells of fraction 3, was active in inducing the inhibitory effect on RNA synthesis in rat Sertoli cells. Co-culture of rat Sertoli cells with germ cells of this fraction also decreased the incorporative of [3H]thymidine into DNA in rat Sertoli cells, from 9061 +/- 3339 to 4766 +/- 526 dpm.2h-1 X 10(6) cells-1 (P less than 0.01), but no such change was found in pig Sertoli cells. A different spermatogenic cell preparation, partially deprived of pachytene spermatocytes (fraction 5), stimulated rat Sertoli cell DNA synthesis (Sertoli alone 7833 +/- 2550, Sertoli cells which had been in co-culture with germ cells of fraction 5, 13,300 +/- 2279 dpm.2h-1 X 10(6) cells-1, P less than 0.05). These inhibitory actions of some germ cells on Sertoli cells were observed together with the previously reported simultaneous stimulatory effect of Sertoli cells on germ cells. These Sertoli cell-germ cell interactions of detected in culture may represent regulatory influences operating in vivo.

Pubertal development in male hypopituitarism

The spontaneous or therapeutically induced pubertal development of 65 male patients with idiopathic hypopituitarism was analysed. Spontaneous puberty occurred in 82% of the patients with prepubertal isolated growth hormone deficiency and in 32.5% of those with impairment in the secretion of more than one pituitary hormone. Out of this group, 36 patients could be studied longitudinally. In 15 patients, the onset of spontaneous puberty was delayed, on average, 3.2 years. It started at a bone age of 10.36 +/- 1.25 "years" and followed a pattern similar to that of normal boys. Testosterone levels at each pubertal stage were not different from those of normal boys. Mean peak height velocity reached 7.27 +/- 1.82 cm/year. In 21 patients with gonadotropin deficiency, hCG treatment was started at a chronological age of 19.04 +/- 2.17 years and a bone age of 12.94 +/- 0.80 "years". Plasma testosterone attained normal adult levels in the majority of boys, while the development of sexual characteristics showed a wide variation. Mean growth velocity during the first year of hCG therapy reached 6.11 +/- 2.47 cm/year. Partial gonadotropin deficiency was diagnosed in two boys. Although testosterone seems today to be, for practical reasons, the replacement therapy of choice, hCG treatment is an alternative for hypopituitary patients with absent gonadotropin function.