Motoyashiki T, Fukamachi M, Morita T, Shiomi H, Ueki H
1st Department of Biochemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima, Japan.
Biol Pharm Bull. 1998 Sep;21(9):889-92. doi: 10.1248/bpb.21.889.
A short-term incubation of isolated rat fat pads with vanadate showed the stimulated release of lipoprotein lipase (LPL) activity and suppression of the rise in extracellular adenosine level. The addition of adenosine to the medium showed inhibition of both the stimulated release of LPL activity and an increase in intracellular cAMP content by vanadate. A progressive increase in 5'-nucleotidase activity in the particulate fraction containing plasma membrane was suppressed by vanadate in a time- and dose-dependent manner, suggesting that vanadate inhibits, in part, the production of adenosine based on a dephosphorylation of AMP. In adipocytes, the inhibition of adenylate cyclase via A1 adenosine receptor is more predominant than the stimulation of adenylate cyclase via A2 adenosine receptor (Londos C. et al., Proc. Natl. Acad. Sci. U.S.A., 75, 5362-5366 (1978)). Therefore, vanadate may stimulate the release of LPL activity from the fat pads by suppressing the rise in extracellular adenosine level, accompanied by the activation of adenylate cyclase activity.
用钒酸盐对分离的大鼠脂肪垫进行短期孵育，结果显示脂蛋白脂肪酶（LPL）活性的释放受到刺激，细胞外腺苷水平的升高受到抑制。向培养基中添加腺苷，结果显示钒酸盐刺激释放LPL活性以及增加细胞内cAMP含量的作用均受到抑制。钒酸盐以时间和剂量依赖性方式抑制了含质膜的颗粒部分中5'-核苷酸酶活性的逐渐增加，这表明钒酸盐部分地基于AMP的去磷酸化抑制了腺苷的产生。在脂肪细胞中，通过A1腺苷受体对腺苷酸环化酶的抑制作用比通过A2腺苷受体对腺苷酸环化酶的刺激作用更为显著（Londos C.等人，《美国国家科学院院刊》，75，5362 - 5366（1978））。因此，钒酸盐可能通过抑制细胞外腺苷水平的升高来刺激脂肪垫释放LPL活性，同时伴随着腺苷酸环化酶活性的激活。
