Effect of Stilboesterol Therapy on Thyrotrophin‐releasing Hormone (Trh) Responsiveness in Males

Abstract

TRH responsiveness was investigated in twenty-four males (aged 66-83 years) undergoing stilboesterol therapy for carcinoma of the prostrate. Twelve were taking 2-6 mg daily by mouth for periods of 5 days to 12 months (mean 5 months) (Group A) and the remainder were on daily i.v. doses of 250-500 mg for periods of 3-10 days (mean 8 days) (Group B). In the former group TRH responsiveness was enhanced compared to age matched controls. A contrary effect was observed in the latter group in that the group mean TRH response was significantly lower than that of Group A or of the control group. Basal serum TSH values were unchanged in Group A compared to controls, but a significant elevation in the basal mean value was observed in Group B. The mechanism of action of stilboesterol in the subjects studied remains to be elucidated. Our data are in keeping with either a hypothalamic or pituitary locus for such actions.

The Thyrotropin (TSH) Profile in Isolated Gonadotropin Deficiency: A Model to Evaluate the Effect of Sex Steroids on TSH Secretion*

“…This effect is presumably related to the estrogen therapy. It has been previously reported that exogenous estrogens may increase the TSH response to TRH in the male, although this is not a uniform observation and does not occur in normal females (1)(2)(3)(4)16). There is also no firm relationship between TSH secretion and endogenous estrogens.…”

“…This is supported by the fact that the administration of ethinyl estradiol to these subjects converted their TSH responses to the normal female pattern. Exogenous estrogen administered to normal males and to those with prostatic carcinoma may increase their TSH responses to TRH (1,16), although this has not been a uniform observation (4).…”

“…However, testosterone may counteract the effect of estradiol, which may explain why normal males tend to have a lower TSH response to TRH than females. (J Clin Endocrinol Metab 57: 415,1983) B OTH androgens and estrogens have been reported to influence the TSH response to TRH, although there is no uniform concensus on their effects (1)(2)(3)(4)(5)(6)(7). Some have reported that estrogens enhance TSH responsiveness (1), whereas others have failed to document any effect (2)(3)(4).…”

Serum levels of prolactin, TSH and gonadotrophins following LRH/TRH - double stimulation tests during the menstrual cycle

“…The TRH double stimulation test, however, could not disclose any modulating properties of oestrogens on Prl and TSH secretion during the cycle. Only pharmacological doses of oestrogens may increase hypophyseal Prl and TSH secretion (Carlson et al 1973;Faglia et al 1973;Mortimer et al 1974;Ramey et al 1975;Reymond & LemarchandBéraud 1976;Smyth et al 1977).…”

Suppression of Testicular Androgenesis by <i>D</i>-Tryptophan-6-Luteinizing Hormone-Releasing Hormone Does Not Affect TSH Secretion in Male Subjects

“…It is known that TSH response to TRH is regulated also by hypothalamic dopamine (DA), which ex erts an inhibitory action on TSH secretion [1], Evidence suggests that estrogens exert a predominant anti-DA effect [6], whereas an opposite action of androgens has not been surely demonstrated. Thus, while changes in serum estrogen levels arc often accompanied by a concomitant variation in pituitary TSH responsiveness to TRH [5,15], conversely a fall in serum androgen levels, as recorded in the present study, does not induce this ef fect.…”