The vascular effect of genistein: what is its mechanism, nitric oxide or PGI2?
To determine the effects and mechanism(s) of genistein on endothelial functions, the model of mesenteric-chamber with intravital fluorescence videomicroscopy and image analysis were used. After preconstriction with norepinephrine (NE; 10(-6) M), vascular responses to different doses of genistein (10(-2)-10(-7) M) were recorded with real time video-camera. The mechanism(s) of vasodilation was also determined by using N(omega)-L-arginine methyl ester (L-NAME; 100 microM), the inhibitor of nitric oxide synthase (NOS inhibitor), and/or indomethacin (INDO; 10 microM), cyclooxygenase inhibitor. The results indicated that the topical application of 10(-2)-10(-7) M genistein on mesenteric microvessels caused the increase in arteriolar diameters from 33% to 48%, respectively. The effects of genistein on mesenteric endothelial-dependent vasodilatation could be mediated through both L-arginine/NO and cyclooxygenase pathways. Our finding indicated that genistein could induce endothelial-dependent vasodilation similar to 17beta-estradiol.
Department of Physiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
Prasong
P
Siriviriyakul
Sirima
S
Khemapech
Khuanying
K
Monsiri
Suthiluk
S
Patumraj
D000818:Animals; D001808:Blood Vessels / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects; D011464:Epoprostenol / Q000378:metabolism*; D005260:Female; D019833:Genistein / Q000494:pharmacology*; D018715:Microscopy, Video; D009569:Nitric Oxide / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation
D009569:Nitric Oxide; D011464:Epoprostenol; D019833:Genistein