Influence of Sex Phase of the Menstrual Cycle on Thyrotropin (TSH) Response to Thyrotropin-Releasing Hormone (TRH) 1

ABSTRACT Serum thyrotropin (TSH) levels were measured before and after acute intravenous administration of 200 μg of synthetic thyrotropinreleasing hormone (TRH) to 33 normal subjects with ages ranging between 18 and 36 yr. Thirteen of them were normal men, 10 normal women on days 7–8 of the menstrual cycle and 10 normal women on days 21–22. The TSH response in the women, considered as a single group, was significantly greater than in the men at 15, 30. 45 and 60 min. Also, the mean overall TSH response was greater for women than for men. The response was significantly greater for women in the preovulatory phase than for women in the postovulatory phase of the menstrual cycle. There was no statistically significant between the response of men and of women on days 21–22 of the cycle. The basal PBI values were not different in 4 groups. The TRH dose relative to body weight was lower for men than for any of the groups of women, but there was no difference between women in the 2 phases of menstrual cycle. Ser...