Motoyashiki T, Miyake M, Morita T, Mizutani K, Masuda H, Ueki H
Department of 1st Biochemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima, Japan.
Biol Pharm Bull. 1998 May;21(5):517-9. doi: 10.1248/bpb.21.517.
Astilbin, a dihydroflavonol rhamnoside isolated from the leaves of Engelhardtia chrysolepis, enhanced the vanadate-stimulated release of lipoprotein lipase (LPL) activity from rat isolated fat pads. N-[2-(Methyl-amino)ethyl]-5-isoquinolinesulfonamide (H-8), a potent inhibitor of cAMP-dependent protein kinase (PKA), markedly inhibited the enhancement by astilbin. Lipolysis in the fat pads was stimulated by astilbin alone in a dose-dependent manner and this stimulation was suppressed in the presence of vanadate, probably due to its antilipolytic action. A significant enhancement by astilbin was observed with increasing effects of vanadate on cAMP content in the fat pads and on cAMP phosphodiesterase (PDE) activity in the particulate fraction although astilbin alone showed only a slight increase in the cellular cAMP content and PDE activity. Astilbin may enhance the vanadate-stimulated release of LPL activity through a synergistic effect on an increase in the cellular cAMP content produced by vanadate accompanied by more potent activation of PKA.
落新妇苷是从黄杞叶中分离得到的一种二氢黄酮醇鼠李糖苷，它能增强钒酸盐刺激的大鼠离体脂肪垫中脂蛋白脂肪酶（LPL）活性的释放。N-[2-(甲氨基)乙基]-5-异喹啉磺酰胺（H-8）是一种有效的环磷酸腺苷（cAMP）依赖性蛋白激酶（PKA）抑制剂，能显著抑制落新妇苷的增强作用。落新妇苷单独就能以剂量依赖的方式刺激脂肪垫中的脂肪分解，而在钒酸盐存在的情况下，这种刺激受到抑制，这可能是由于其抗脂解作用。尽管落新妇苷单独作用时细胞内cAMP含量和磷酸二酯酶（PDE）活性仅略有增加，但随着钒酸盐对脂肪垫中cAMP含量和微粒体部分中cAMP磷酸二酯酶（PDE）活性的影响增强，落新妇苷有显著增强作用。落新妇苷可能通过对钒酸盐产生的细胞内cAMP含量增加的协同作用，伴随更有效的PKA激活，来增强钒酸盐刺激的LPL活性释放。
