Doris R, Vernon R G, Houslay M D, Kilgour E
Hannah Research Institute, Ayr, Scotland, U.K.
Biochem J. 1994 Jan 1;297 ( Pt 1)(Pt 1):41-5. doi: 10.1042/bj2970041.
The effect of growth hormone (GH) in vivo on the Gi-mediated anti-lipolytic signalling system of rat adipocytes has been investigated. Lowering of serum GH levels, by treatment of rats with an antiserum (anti-rGH) specific for rat GH, increased the sensitivity of adipocytes to the anti-lipolytic agonists N6-phenylisopropyladenosine (PIA) and prostaglandin E1. This occurred in the absence of any change in PIA binding to adipocyte membranes. Immunoblot analysis of adipocyte membranes revealed that lowering of serum GH resulted in at least a 3-fold increase in the levels of alpha-subunit of Gi2, but had no effect on the alpha-subunits of Gi1 and Gi3 nor on the 42 and 45 kDa forms of the alpha-subunit of Gs. Replenishment of serum GH, by concurrent administration of ovine GH to rats, prevented all of these effects of anti-rGH. It is concluded that GH down-regulates the amount of Gi2 alpha-subunit in adipocyte membranes, resulting in a decrease in the sensitivity of the cells to anti-lipolytic agonists.
研究了生长激素（GH）在体内对大鼠脂肪细胞Gi介导的抗脂解信号系统的影响。用针对大鼠GH的抗血清（抗rGH）处理大鼠以降低血清GH水平，可增加脂肪细胞对抗脂解激动剂N6-苯基异丙基腺苷（PIA）和前列腺素E1的敏感性。这一现象发生在PIA与脂肪细胞膜结合无任何变化的情况下。对脂肪细胞膜进行免疫印迹分析显示，血清GH降低导致Gi2α亚基水平至少增加3倍，但对Gi1和Gi3的α亚基以及Gsα亚基的42 kDa和45 kDa形式均无影响。通过同时给大鼠注射羊GH来补充血清GH，可防止抗rGH的所有这些作用。得出的结论是，GH下调脂肪细胞膜中Gi2α亚基的量，导致细胞对抗脂解激动剂的敏感性降低。
