Determination of thein VivoRate of Progesterone Secretion by the Ovary of the Pig During the Luteal Phase of the Estrous Cycle11

Abstract

A method for the simultaneous collection of ovarian venous and arterial blood samples from pigs was developed. The method insures the collection of the total ovarian venous blood uncontaminated by extra-ovarian blood. Progesterone was not detected in the arterial samples collected simultaneously with ovarian venous samples from the same animals. The right ovary of the pig secreted an average of 1.41, 2.23 and 1.41 [mu]g of progesterone/ml of ovarian venous plasma on days 7, 11 and 13 of the 21-day estrous cycle, respectively. Progesterone was secreted by the ovary at a rate of 7.2, 13.4 and 7.6 [mu]g/ovary/min. on these same days of the estrous cycle, respectively. If it is assumed that all of the progesterone is secreted by the corpora lutea, the secretory rate can be expressed as 3.94, 2.96 and 2.74 ug of progesterone secreted per g of luteal tissue per min on days 7, 11 and 13, respectively.