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.