Effects of Estradiol-17β and Progesterone on Prostaglandins F in Sheep Uteri and Uterine Venous Plasma1

Abstract

The effects of estrogen and progesterone on the content and concentration of prostaglandins F (PGF) in uterine tissue and venous plasma were investigated in ewes. Estradiol-17β (3 (.5 mg intramuscularly) on days 9 and 10 post-estrus increased the uterine venous plasma concentration (P<.01) and endometrial content and concentration (P<.05) of PGF in intact ewes sampled on day 11. The same dose of estradiol on days 4 and 5 had no effect on uterine venous plasma concentration or endometrial content of PGF in ewes sampled on days 6 or 6 and 9. After prior treatment with progesterone (10 mg per day on days 1 through 5) estradiol on days 4 and 5 did increase uterine venous PGF on days 6 and 9. Progesterone alone had no effect. Myometrial content and concentration of PGF were higher on day 11 than on day 6 regardless of whether ewes had received estradiol or corn oil. In ovariectomized ewes, two injections of 12.5 µg of estradiol 12 hr apart increased PGF in uterine venous plasma 12 hr after the second injection in both control and progesteroneprimed (5 days) ewes.