The action of 7-oxa-13-prostynoic acid on spontaneous contractions and on PGF-2alpha and angiotensin II elicited contractions has been studied on rat uteri excised during pro and metaoestrus. At the concentration of 5 x 10-6M, the compound does not alter the spontaneous contractions of proestrus uteri and suppresses the phasic component of PGF-2alpha-elicited contractons. At the concentration of 5 x 10-5M, 7-oxa-13-prostyno?c acid inhibits spontaneous contractions, and inhibits PGF-2alpha-elicited contractions. In metaoestrus uteri, the inhibitory effect is not competitive. 7-oxa-13-prostyno?c acid is also able to inhibit non competitively the contractor effect of angiotensin II in proestrus uteri. This result, together with those of previous investigations performed using other prostaglandin inhibitors, suggest that the contractor effect of angiotensin II on the uterus is partially mediated by endogenous prostaglandins.
Angiotensin II Animals