Endothelium-dependent gender differences in the response of the rat pulmonary artery to the thromboxane mimic (U46619).
The pulmonary arteries of rats were studied in order to determine the existence of sexual dimorphism. Gender differences, in the sensitivity (EC50) and maximum contractility (Tmax) of ring preparations of the main pulmonary arteries of adult male and female rats, were evaluated with the synthetic endoperoxide analog [(15S)]-hydroxy-11 alpha,9 alpha-(epoxymethano)-prosta-5Z, 13E-dienoic acid,] (U46619) and norepinephrine. There were no significant gender differences in the Tmax values obtained with either U46619 or norepinephrine. However, when the intimal surface of vessel segments from female rats was rubbed, U46619 but not norepinephrine elicited a significantly lower Tmax. In contrast, no change in Tmax was observed with denuded vessel segments from males. Removal of the endothelium did not significantly affect the EC50 of U46619 or norepinephrine in segments from either sex. The inhibitory effect of verapamil on the U46619-induced contractile response was studied on both intact and denuded vessels from rats of both gender. The Tmax of intact vessels from males but not females was significantly attenuated by verapamil (P less than .05). The EC50 values with verapamil were not significantly different in any of the vessel preparations. We suggest that the endothelium of the pulmonary artery of female rats significantly potentiates the contractile response to U46619 and attenuates the inhibitory effect of verapamil.
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000818:Animals; D004727:Endothelium / Q000187:drug effects; D005260:Female; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000187:drug effects*; D051381:Rats; D012737:Sex Factors; D014661:Vasoconstriction / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
D011450:Prostaglandin Endoperoxides, Synthetic; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D014700:Verapamil