Prostaglandin binding to different cell types of human uterus: quantitative light microscope autoradiographic study

Five human uteri of the menstrual cycle were analyzed by quantitative light microscope autoradiography to determine which uterine cell types contain prostaglandin (PG) binding sites. The results showed that stromal cells, glandular epithelium, elongated and circular smooth muscles, arterioles and erythrocytes in lumen of arterioles contained numerous PGE and very few or no detectable PGF2 alpha binding sites. The grains which were present when incubated with [3H]PGE2 alone completely disappeared following coincubation with excess unlabeled PGE2 but not with excess unlabeled PGA1. Analysis of grain count data revealed that PGE binding sites in arterioles were lower than those in other uterine cell types and PGE binding sites in endometrial cells of proliferative phase uteri were higher than those in secretory phase uteri (P less than 0.05). Thus the present results demonstrate that all the cell types, including arterioles of human uterus of the menstrual cycle, contain PGE and minimal PGF2 alpha binding sites. This suggests that PGE binding sites in different cell types of human uterus subserve diverse effects of PGEs.