Increase of ovarian progesterone secretion by β2-adrenergic stimulation in oestrous rats

Oestrous rats were anaesthetized with pentobarbital and one of the femoral arteries, femoral veins and utero-ovarian veins were cannulated. Five min blood fractions were collected from the ovary for 50 min. Following two control fractions fenoterol, noradrenaline, isoproterenol (0.5 microgram/min) or 0.9% NaCl (0.02 ml/min) were infused iv for 40 min. In a group of oestrous animals fenoterol was given locally to the ovarian bursa. Blood pressure and the ovarian venous outflow were continuously recorded and blood levels of progesterone (P) and oestradiol-17 beta (E2) were determined by RIA. Fenoterol administered iv increased P secretion without altering ovarian blood flow, whereas noradrenaline and isoproterenol had no effect on P secretion. Fenoterol administered locally stimulated both P and E2 secretion, and this was prevented by iv infusion of propranolol. It is suggested that ovarian beta 2-adrenergic receptors have a regulatory role in ovarian hormone secretion.