SERUM THYROTROPHIN, PROLACTIN AND GROWTH HORMONE, RESPONSE TO TRH DURING OESTROGEN TREATMENT

Abstract

ABSTRACT The serum levels of thyrotrophin (TSH), prolactin (PRL) and growth hormone (GH) and the response of these hormones to 500 μg thyrotrophin-releasing hormone (TRH) iv were studied in menstruating women. in post-menopausal women before and after 2 mg oestradiol valerate for 5 consecutive days, and in men on long term oestrogen treatment. Oestrogen treatment had no effect on basal serum TSH levels, which were within the normal range in all groups. The TSH response to TRH was not different in menstruating and post-menopausal women and was not changed in the latter group after oestrogen treatment. In men treated chronically with oestrogens, the TSH response to TRH was similar to that found in normal male subjects. There was no difference in basal levels of serum PRL between males and menstruating females. In the post-menopausal women, however, basal levels of serum PRL was significantly decreased, but rose during oestrogen treatment to serum levels normally found in menstruating women. In the oestrogen treated males basal serum PRL levels were significantly higher than in untreated men. The PRL response to TRH was significantly greater in females than in males, but in the oestrogen treated males the PRL response to TRH was greatly increased and almost of the same magnitude as the response in females. There was no difference in PRL response between menstruating and post-menopausal women, and oestrogen treatment of the latter group had no significant effect on the PRL response. Basal levels of serum GH did not differ between the groups. In the group of 9 post-menopausal women one subject showed a small GH response to TRH prior to oestrogen treatment, while 7 subjects showed GH responses to TRH after oestrogen treatment. In the group of 5 chronically oestrogen treated men, 2 subjects had increased serum levels of GH after TRH. Thus our data show that oestrogen administration may induce PRL release in human subjects, while oestrogens seem to play a far less important role in the regulation of GH and TSH secretion.