Effect of prolactin on the production of progesterone by mouse ovaries in vitro

M.R.C. Unit of Reproductive Biology, 39 Chalmers Street, and * Hormone Laboratory, Department of Obstetrics and Gynaecology, University of Edinburgh, Edinburgh, EH3 9ER, U.K. Prolactin constitutes part of the luteotrophic complex necessary for the maintenance and secretory activity of the CL in the rat (Evans, Simpson, Lyons & Turpeinen, 1941; Astwood, 1941), mouse (Kovacic, 1964), rabbit (Spies, Hilliard & Sawyer, 1968), hamster (Greenwald & Rothchild, 1968), ferret (Donovan, 1963), pig (du Mesnil du Buisson, 1973), and sheep (Denamur, Martinet & Short, 1973). There is also evidence from in-vitro studies that low concentrations of prolactin are essential for the production of progesterone by preovulatory human granulosa cells (McNatty, Sawers & McNeilly, 1975; McNatty, Bennie, Hunter & McNeilly, 1976) while high concentrations are inhibitory (McNatty et al., 1976). In the present study the effect of various concentrations of prolactin on the production of progesterone by mouse ovaries in organ culture with or without