HORMONE-DEPENDENT CHANGES IN A-FORM AND B-FORM OF PROGESTERONE-RECEPTOR

The influence of different estrogen and/or progesterone treatments on concentrations of A and B forms of progesterone receptor (PR-A and PR- B) in the different cell types of chick oviduct was studied. A semiqua ntitative immunohistochemical assay for cellular PR concentrations was developed using a computer-assisted image analysis system. The staini ng intensity of nuclear PR in the basal layer of epithelial cells, gla ndular, smooth muscle and mesothelial cells was analysed separately us ing two monoclonal antibodies, PR6 and PR22. The measured concentratio ns of PR varied between different cell types and from cell to cell. A significant decrease in PR concentration, as noted by a decrease in st aining intensity, was observed in all cell types studied 2 or 6 h afte r a single injection of progesterone with or without simultaneous estr ogen administration. The decrease was also verified with immunoblottin g and an immunoenzymometric assay (IEMA) for chicken PR. After down-re gulation the concentration of PR recovered to the control level within 48 h after progesterone or estrogen administration. Estrogen administ ration alone was observed to cause changes in the concentration of PR- A only, having little or no effect on PR-B concentration depending on the cell type studied. These findings indicate that estrogen and proge sterone cause cell-specific changes not only to the total concentratio n of PR but also to the cellular ratio of PR-A and PR-B. Copyright (C) 1996 Elsevier Science Ltd