The objectives were to measure thyroid stimulating hormone (TSH) levels in human follicular fluid (FF) and compare them with serum levels. Serum and FF samples were obtained fi om women (n = 41) undergoing in vitro fertilization/embryo transfer, gamete intrafallopian transfer and zygote intrafallopian transfer. Ovulation induction teas achieved using human menopausal gonadotropins and human chorionic gonadotropin (hCG) after pituitary suppression with a gonadotropin releasing hormone agonist. Blood samples obtained on the day of hCG injections were assayed for TSH. Follicular fluids were obtained at the time of oocyte retrieval (approximately 34 hours after hCG injection). Serum and FF TSH levels were measured using an enzyme immunoassay. The correlation between serum and FF TSH levels was determined. Comparison between mean serum and FF levels was done using Student's t test after logarithmic transformation of the data. Levels of TSH in FF (1.71 +/- 0.14 mu IU/mL, mean +/- SEM) were not different (P > .05) from levels in serum (1.43 +/- 0.10). Serum and FF levels correlated positively (r = .7). TSH appears to be present in human FF, and the levels in FF are similar to those in serum.
