Immunoreactive endothelin-1, endothelin-2 and big endothelin-1 in follicular fluids of women undergoing ovulation induction for in-vitro fertilization

Endothelin-like immunoreactivity specific for endothelin-1 (ET-1), endothelin-2 (ET-2) or big endothelin-1 (big ET-1) was measured, using commercially available radioimmuno-assay kits, in follicular fluid collected at the time of oocyte aspiration from 36 women undergoing ovulation induction by human menopausal gonadotrophin (HMG). The relation-ship of ET concentrations to HMG dose, peak serum oestra—-diol concentration, the number and size of follicles (by ultrasound), the number of retrieved oocytes and the fertilization rate per retrieved oocyte were studied. Overall, 94% of follicular fluid samples were positive for ET-1, 92% were positive for ET-2, and 100% were positive for big ET-1. Mean ET-1, ET-2 and big ET-1 concentrations were 17.23±12.20, 32.42± 14.32 and 34.55± 16.34 pg/ml respectively. Endo-thelin-like immunoreactivity in follicular fluid samples was found in an order of ET-1