PITUITARY GONADOTROPHINS IN THE EWE AT DIFFERENT STAGES OF THE ESTROUS CYCLE

Abstract

The content of FSH, LH, and LTH in ewe pituitaries has been determined at the following stages of the estrous cycle: 4 hours, 35 hours, 10 days, and 15 days after first acceptance of the ram. Pituitary FSH and LH decreased significantly between 4 hours and 35 hours after first acceptance, and then returned to proestrus levels by the fifteenth day of the cycle. Pituitary LTH content did not vary significantly during the estrous cycle with the assay techniques employed. It is suggested that FSH plays an active role in the induction of ovulation in the ewe and that the assumption of a specific release of LH may not be valid for this species.