RELEASE OF LUTEINIZING HORMONE IN ANDROGENIZED EWES AFTER PROSTAGLANDIN-INDUCED LUTEOLYSIS OR LUTEINIZING HORMONE RELEASING HORMONE

M.R.C. Unit of Reproductive Biology, 2 Forrest Road, Edinburgh, EHI 2QW(Received31 October1977)Exposure to testosterone during development masculinizes the genitalia and behaviour of ewes (Clarke, Scaramuzzi & Short, 1976a; Clarke, 1977) and causes ovulatory failure (Clarke, Scaramuzzi & Short, 1977). Androgenized ewes do not release luteinizing hormone (LH) after oestrogen treatment during anoestrus (Clarke, Scaramuzzi & Short, 1976b). These experiments were performed to determine the site of action (hypothalamus or anterior pituitary gland) of prenatally administered androgens in blocking the preovulatory release of LH.Finnish Landrace × Dorset Horn ewes were used in their second breeding season after exposure to testosterone between days 30 and 80 (D30–80, n= 6), 50 and 100 (D50–100, n= 1), 70 and 120 (D70–120, n= 6) or 90 and 140 (D90–140, n= 5) of prenatal life (Clarke et al.1976a). Eight normal ewes served as controls. To facilitate