THE ADRENOTROPIC RECEPTORS OF THE CAT UTERUS

¹ Department of Pharmacology, West Virginia University Medical Center, Morgantown, West Virginia

The relative potencies of epinephrine, norepinephrine, and isoproterenol as well as the blocking actions of dichloroisoproterenol and phenoxybenzamine have been studied in isolated uteri from cats in various hormonal states. The uterus of the virgin cat is relaxed by catecholamines through the action of beta receptors. The uterus of the cat under the influence of progesterone is stimulated, an alpha effect. The uterus of the cat under the influence of estrogen has a more variable response and seems to be intermediate. The evidence indicates that both receptors are present in various functional states and that the changes in response correlated with hormonal alterations are due to a shift in the balance of the receptors.