Effects of glycyrrhizin on production of vascular aldosterone and corticosterone

This study is to confirm the role of glycyrrhizin on blood pressure and to test the effects of glycyrrhizin on production of vascular aldosterone and corticosterone in rats. Male Wistar rats received glycyrrhizin (Sigma) 200 mg/kg/day p.o, for 5 weeks, and blood pressure was monitored by a pressure transducer, Systolic blood pressure significantly increased in Wistar rats treated with glycyrrhizin compared to that without glycyrrhizin. Mesenteric artery perfusion ex vivo and presser responses to norepinephrine were perf ormed. The presser responses to norepinephrine in mesenteric arteries treat ed with glycyrrhizin were significantly increased. The perfusate from the m esenteric arteries was collected and applied to a Sep-Pak C 18 cartridge co lumn, used for reverse-phase high-performance liquid chromatography, and me asured for both aldosterone and corticosterone by radioimmunoassay, Levels of aldosterone were decreased but those of corticosterone increased in perf usate from arteries treated with glycyrrhizin, RT-PCR showed that glycyrrhi zin inhibited the expression of 11 beta-HSD2 and CYP11B2 mRNA in mesenteric arteries. These results confirm that glycyrrhizin is able to induce hypert ension, and provide evidence that it inhibits the transcriptions of both 11 beta-HSD2 and CYP11B2 in the vasculature, leading to lower aldosterone and higher corticosterone production in vessels, and increased vasoconstrictor responses to norepinephrine.