Control of follicular maturation in the mouse by a nonsteroidal regulator from sheep follicular fluid

Follicular fluid from sheep ovaries was gel-chromatographed on Sephadex G-100, and the retarded active fraction (Fr-IV, Kav = 1) was rechromatographed on G-25 (GF2). When injected into pseudopregnant mice, it did not affect corpus luteum function, but at the time of the termination of pseudopregnancy ovulation was suppressed. A dose of 20 micrograms GF2 when injected into cycling mice inhibited follicular maturation and ovulation. Plasma progesterone levels were also reduced, indicating the role of a nonsteroidal factor in follicular maturation, ovulation, and luteinization.