Presence of Leukemia Inhibitory Factor and Interleukin‐12 in Human Follicular Fluid During Follicular Growth

PROBLEM: Cytokines have been shown to be present in human follicular fluid and have regulatory functions on follicular maturation. The presence of leukemia inhibitory factor (LIF) and interleukin (IL)-12 in human follicular fluid obtained at different stages of maturation was investigated. METHOD OF STUDY: Follicular fluids and granulosa cells were obtained from preovulatory and immature follicles. Follicular fluids from both groups were assayed for IL-12 and LIF by enzyme-linked immunosorbent assay. Granulosa cells from preovulatory and immature follicles were treated with human chorionic gonadotropin (hCG) in vitro and subsequent LIF and IL-12 production were measured. RESULTS: The average concentration of LIF was significantly higher in preovulatory follicles (7.6 +/- 1.3 pg/ml, n = 24) than in immature follicles (2.0 +/- 1.3 pg/ml, n = 6). The concentration of IL-12 was significantly higher in follicular fluid obtained from immature follicles (10.9 +/- 5.0 pg/ml) than in preovulatory follicles (1.3 +/- 0.4 pg/ml). hCG only stimulated LIF production from mature granulosa cells; it had no effect on IL-12 production. CONCLUSIONS: IL-12 and LIF are present in follicular fluid and their levels are regulated differently during follicular maturation. hCG stimulates LIF production from granulosa cells in vitro.