Jugular and ovarian venous profiles of progesterone and associated endometrial progesterone concentrations in pregnant and non-pregnant ewes

Jugular and ovarian venous profiles of progesterone and endometrial progesterone concentrations were measured in pregnant and non-pregnant ewes. Mean jugular concentrations were not significantly different (3·12v.2·39 μg/l). The incidence of progesterone concentrations above a chosen threshold was significantly greater in the ovarian vein than in the jugular vein (P < 0·05) and was greater (P > 0·05) in the ovarian venous plasma of pregnant than of non-pregnant ewes. Mean endometrial progesterone concentrations were significantly higher in pregnant than in non-pregnant ewes (T < 0·05). It is suggested that the lower progesterone concentrations in the ovarian veins of non-pregnant ewes may have a rôle in pregnancy failure and that ovarian venous concentrations may influence endometrial progesterone concentrations.