Biological activity of progesterone-dihydropyridimidine derivative on perfusion pressure and coronary resistance in isolated rat heart

Experimental studies suggest that progesterone can regulate blood pressure. Nevertheless, there is scarce information about the effects of progesterone and its derivatives at cardiovascular level. In addition, to date the cellular site and mechanism of action of progesterone at cardiovascular level is also unclear. In order, to clarify on those phenomena, we evaluated the effects of progesterone and progesterone-dihydropyridimidine derivative on perfusion pressure in isolated rat heart using Langendorff flow model. Our results demonstrated that progesterone-derivative at a concentration of 10^-9 mM, significantly increase the perfusion pressure (p = 0.006) and coronary resistance (p = 0.005) in isolated heart. The activity exerted by progesterone-dihydropyridimidine derivative on perfusion pressure [10^-9 to 10^-4 mM] was blocked in presence of indomethacin [10^-6 mM] and PINANE TXA2 [10^-6 mM]. These data suggest that activity induced by progesterone-derivative on perfusion pressure and coronary resistance involves the thromboxane A₂ (TXA₂) synthesis and secretion.