Concentrations of unconjugated oestradiol and progesterone in blood plasma and prostaglandins F-2 and E-2 in oviducts of hamsters during the oestrous cycle and in early pregnancy

Abstract
Blood and tissue samples were obtained from hamsters during the estrous cycle and for the first 4 days of pregnancy. Maximum steroid and PG [prostaglandin] concentrations occurred around ovulation with continuously declining levels afterwards, indicating that ovarian steroids, at least in part, may be responsible for oviducal PG synthesis.