Inhibition of fetal growth and survival by testosterone administration to pregnant sheep

Testosterone (as testosterone enanthate, 250 mg i.m. every 2 wk) was administered to pregnant ewes (n = 16), and injections of vehicle were used in 10 control pregnant ewes between days 75 of gestation and term (day 147). Fetal survival (7 of 16 in the treated group versus 10 of 10 in the controls) and growth (birth weights 4.00 +- 0.51 kg in the treated group versus 5.79 +- 0.93, mean +- SD, in the controls) were markedly impaired by testosterone administration. The mechanism of the testosterone effect is unknown, but could be through metabolism to estrogens by the feto-placental unit. These results imply that alterations in the production or metabolism of androgens by the mother or the feto-placement unit may exert important effects on fetal growth and survival.

Increases in serum concentrations of follicle-stimulating hormone (FSH) during thyrotrophin-releasing hormone (TRH) infusions in normal men

Increases in serum FSH values to approximately 50% above basal concentrations were found during TRH infusions of 2.0 microgram/min into normal men (n = 10). These increases could not be explained by cross-reactivity of thyrotrophin (TSH) in the FSH assay. No significant change was found in serum concentrations of FSH during saline infusions (n = 4) nor in LH concentrations during either TRH or saline infusions. Many previous studies using single injections of TRH have failed to demonstrate changes in serum FSH concentrations. It is possible that prolonged infusions of TRH, as used in this study, are more likely to lead to non-specificity of the effects of this tripeptide on pituitary hormone secretion.

The effect of luteinizing hormone-releasing hormone in hypogonadotrophic eunuchoidism

Fourteen patients with hypogonadotrophic eunuchoidism (HE), 10 males and 4 females, received luteinizing hormone-releasing hormone (LH-RH) as 4-h intravenous infusions of 0.2 μg/min or as subcutaneous (sc) injections of 200 μg. Repeated LH-RH administration over 4 days (200 μg sc daily) was undertaken in 8 patients. Eight of the 10 males and all 4 of the females were found to have definite elevations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) following their first exposure to exogenous LH-RH. The patients included 2 males and 1 female with variant forms of HE, all of whom showed responses of both gonadotrophins.

When the first exposure of HE patients to exogenous LH-RH was as a 4-h infusion, the biphasic pattern of LH increase characteristic of normal adults was not found. Instead, a monophasic and qualitatively small LH increase occurred, similar to that found in pre-pubertal children and in anorexia nervosa. In 2 patients with an initially abnormal LH response, a 4-h LH-RH infusion following 4 days of LH-RH injections (200 μg sc/day) produced a normal biphasic LH increase. These results imply that maintenance of the two pools of pituitary LH demonstrable in normal adults depends on adequate production of endogenous LH-RH.

Increases in FSH following the initial exposure to LH-RH were generally as great or greater than those of normal adults in spite of the fact that LH responses tended to be smaller than those of adults. Four days of LH-RH administration (200 sc daily) did not lead to consistent increases in gonadotrophin responsiveness. Increases of testosterone or oestradiol production could not be demonstrated, even with 4 to 5 days of LH-RH administration. Exogenous sex hormone therapy markedly inhibited gonadotrophin responsiveness to LH-RH.

Pituitary autonomy in hyperprolactinemic secondary amenorrhea: results of hypothalamic-pituitary testing

Twenty-seven women with secondary amenorrhea of greater than six months duration were subjected to multiple testing of hypothalamo-pituitary function. They were divided into normo-prolactinemic (Group 1 mean serum prolactin (PRL) 9.8 ng/ml; range 6.8 to 13.0 ng/ml; n=9) and hyperprolactinemic (Group 2 mean 37.5 ng/ml; range 19.2 to 93.7 ng/ml; n=18) groups on the basis of 4 weekly baseline determinations. Group 2 had significantly (P less than .05) lower serum LH and urinary pregnanediol levels than did Group 1; there was no statistical difference between the groups in serum FSH, T4, T3 or urinary estrogen measurements. Two women in Group 2 were found to have a pituitary chromophobe adenoma. Group 2 women showed no significant rises in serum PRL following stimulation tests with thyrotropin releasing hormone (TRH, 200 microng iv) and metoclopramide (10 mg orally), which caused significant responses in Group 1. The TSH response to TRH was, however, preserved in Group 2, while it was subnormal in Group 1 subjects. Both groups showed similar FSH and LH responses to luteinizing hormone-releasing hormone (LHRH, 25 microng iv). No significant suppression of serum PRL was seen in Group 2 patients given L-Dopa (500 mg orally),, which produced a significant response (P less than 0.05) in Group 1 subjects, while all patient showed marked reduction in serum PRL values following 2-bromo-alpha-ergocryptine (CB-154, 2.5 mg orally). When compared with other Group 2 members, the 2 cases with proven pituitary adenomata gave similar responses to the stimulation-inhibition tests and were not clearly distinguished on this basis. We conclude: 1. The pattern of PRL responses to dynamic tests, although of pathophysiological interest an autonomous pituitary lesions in patients with hyperprolactinemic secondary amenorrhea. 2. Such dynamic tests, although a pathophysiological interest, provide no clinical information additional to that provided by the mean basal serum PRL value. 3. In clinical practice, such dynamic tests should be confined to patients with mean serum PRL levels at around the upper limit of the normal range.

Prolonged intravenous infusions of LH-releasing hormone into normal men

Five normal men received constant intravenous infusions of luteinizing hormone-releasing hormone (LH-RH), 0.2 mug/min, for 14-19 hours. Serum levels ofluteizining hormone (LH) revealed a biphasic pattern of increase, reaching maximal values by 4 hours after the infusions began, then remained near that level until the infusions ceased. Serum follicle stimulating hormone (FSH) levels rose gradually to maximal values by 6-13 hours and maintained this level until the end of the infusions. Testosterone (T) levels revealed gradual increases throughout the infusions. These results confirm an increase in serum T levels with prolonged endogenous gonadotrophin stimulation. This is in contrast to the inability of several previous studies to demonstrate an increase in T levels following the relatively short gonadotrophin elevation produced by single-shot LH-RH administration. The T increases produced, however, were quantitatively much less than those reported during prolonged LH-RH infusions in rams, suggesting that the human testis is less responsive to endogenous gonadotrophin stimulation than is that of the ram. In addition, prolonged LH-RH stimulation did not cause pituitary refractoriness in men as has been described in animals.

The association of D-group chromosomal translocations and defective spermatogenesis

D-group chromosome translocations have been associated in isolated cases with infertility in males. In this study, we demonstrated the effect of a translocated D-group chromosome on spermatogenesis as it had segregated among three male members of one family. Although the father, who carried the translocation, was obviously fertile, the effects of the translocations on his sperm were noted in the morphologic examination. This study demonstrates the need for more careful evaluation of patients with chromosomal abnormalities for effects on spermatogenesis. Furthermore, it shows the possibility of autosomal chromosomal influences on testicular function.