Induction of macrophage migration inhibitory factor in human ovary by human chorionic gonadotrophin

The role of macrophage migration inhibitory factor (MIF) in human ovarian f unction remains obscure. The aim of this study was to investigate how MIF w as related to ovulation by quantitative analysis of serum, follicular fluid and culture medium of granulosa cells obtained from in-vitro fertilization (IVF) and embryo transfer patients. Serum MIF concentrations in ovarian st imulation cycles for IVF-embryo transfer were higher at day 1 (median 92.6 ng/ml), which took place 35 h after human chorionic gonadotrophin (HCG) adm inistration and just before the retrieval of oocytes, than those before day -6 (12.1 ng/ml), at day -5 to about day 0 (17.5 ng/ml) or at day 2 to abou t day 14 (8.2 ng/ml). MIF concentrations in the follicular fluid (113.4 ng/ ml) obtained in ovarian stimulation cycles for IVF-embryo transfer were sig nificantly higher than in serum (72.0 ng/ml) collected at the same time. MI F concentrations in the follicular fluid in natural cycles were higher in t he ovulatory phase (51.6 ng/ml) than in the late follicular phase (13.8 ng/ ml). MIF concentrations in the culture media of granulosa cells increased f rom 3.2 ng/ml to 7.2 ng/ml with HCG stimulation, and decreased from 2.4 ng/ ml to 1.2 ng/ml when stimulation was withheld. These results indicate that HCG can induce the elevation of serum and follicular fluid MIF concentratio ns through the stimulation of ovarian cells, and that MIF is probably invol ved in the mechanism of ovulation.