Possible contribution of follicular interleukin-1β to nitric oxide generation in human pre-ovulatory follicles

Abstract

The aim of this study was to investigate the relationships between follicular nitric oxide (NO) metabolite concentrations and several related variables, with special reference to follicular interleukin-1β (IL-1β). The follicular fluid from the leading and secondary follicles was collected individually from 20 women undergoing in-vitro fertilization (IVF) treatment, and the concentrations of nitrite (NO2-) and nitrate (NO3-) were determined fluorometrically using 2,3-diaminonaphthalene. Both follicular nitrite (r = 0.42, P < 0.01) and nitrate (r = 0.49, P < 0.001) were found to be significantly correlated with follicular IL-1β concentrations. There were also significant positive correlations between follicular nitrate and the number of oocytes retrieved (P < 0.01) and serum oestradiol concentration on the day of human chorionic gonadotrophin (HCG) administration (P < 0.05). When follicular cells were incubated in vitro with 10 ng/ml of IL-Iβ for 24 h, nitrate generation was significantly (P < 0.01) elevated compared with the control. In conclusion, our study demonstrates that follicular IL-1β and the number of developing follicles are significant variables that affect follicular NO concentrations, and points to the possible contribution of IL-1β to NO generation in human pre-ovulatory follicles.