Increase in ovulation rate after immunization of Merino ewes with a fraction of bovine follicular fluid containing inhibin activity

Abstract

Affinity chromatography of bovine follicular fluid using Matrix gel Red A resulted in a 20-fold increase in inhibin-like specific activity assessed in a mouse ovulation inhibited test system. When this material was emulsified with Freund''s adjuvant and injected into adult Merino ewes their mean ovulation rate was increased from 1.2 to 2.3 (P < 0.01). Follicles of diameter .gtoreq. 3.5 mm and 2-3.4 mm were also increased (4.33 vs 2.25 and 5.39 vs 2.44 per ewe respectively). The ovulation rate response was variable and transient. Length of oestrous cycles, number of granulosa cell per follicle and seasonal oestrous patterns were not affected. Plasma from the immunized ewes contained antibodies to the immunogen and reversed the ovulation-inhibiting effects of bovine follicular fluid in mice.