Progesterone Levels in Corpora Lutea and Ovarian Effluent Blood of the Ewe

Abstract

Progesterone levels in corpora lutea were studied at 4, 6, 8, 10, 12 and 14 days after estrus in 38 normal ewes. The average weight and total progesterone content of corpora lutea changed significantly during the estrual cycle. Average weight and progesterone concentration were both negatively correlated with number of corpora lutea (—.56 and —.39, respectively). Total luteal weight was correlated with number of corpora lutea (0.87), and total progesterone content was correlated with total luteal weight (0.48). Relationships also were determined between hormone content of corpora lutea and ovarian effluent blood plasma progesterone at days 6, 10 and 14 of the cycle in 12 normal and 12 superovulated ewes. The over-all regression of blood plasma progesterone concentration on total luteal progesterone in normal ewes was statistically significant. Total luteal weights of superovulated ewes decreased significantly from day 6 to 14 after ovulation. Blood flow rate in these ewes was correlated with total luteal weight (0.56). Gross, between-sheep-within-day, and between-ovary-within-sheep regressions of blood plasma progesterone concentration on total luteal progesterone were significant. The gross regression of secretory rate on luteal progesterone content was significant and thatbetween-ovary-within-sheep approached significance. The data support the hypothesis that luteal progesterone content is indicative of the level of function of corpora lutea in terms of the amount of hormone released into the blood. Copyright © 1963. American Society of Animal Science . Copyright 1963 by American Society of Animal Science