Prostaglandin Receptors in the Human, Monkey and Hamster Uterus

Abstract

An in vitro tissue slice incubation system has been used to measure uptake and binding of 3H-labeled prostaglandins by uterine tissues from the human, monkey and hamster. Specific binding of prostaglandin E1 (PGE1) and PGF2α was demonstrated in rhesus monkey myometrium, but not endometrium, and in human myometrium. Specific binding of PGE2 but not PGF1α was present in hamster uterus throughout the estrous cycle. Variations in prostaglandin specific binding during the estrous cycle, and in pregnancy of the hamster, and demonstration of prostaglandin concentrative capacity of the hamster uterus, were indicative of the presence of true prostaglandin receptors in the uterus. Quantitative estimates of PGE1 binding in the hamster uterus gave values for the association constant of 5.8 and 16.4 × 109M−1 and values for receptor concentration of 3.7 and 4.1 × 10−12 moles⁄100 mg tissue for whole uterus and myometrium, respectively. Relative affinities of some prostaglandins for PGE1 binding sites in the hamster uterus were 16,16-dimethyl PGE1 = PGE1 = PGE2 > 15(S)15-methyl PGE1 methyl ester = 13,14-dihydro PGE1 = PGA1 = PGE1 methyl ester » PGF2α = 15-keto PGE1. Treatment of ovariectomized hamsters with estradiol decreased PGE1 and PGF2α specific binding in the uterus in a dose-dependent manner. Progesterone increased b’oth PGE1 and PGF2α specific binding. (Endocrinology95: 55, 1974)