ENHANCED COUPLING OF ADENYLATE-CYCLASE TO LIPOLYSIS IN PERMEABILIZED ADIPOCYTES FROM TRAINED RATS
ENHANCED COUPLING OF ADENYLATE-CYCLASE TO LIPOLYSIS IN PERMEABILIZED ADIPOCYTES FROM TRAINED RATS
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DOI：
10.1152/jappl.1991.71.1.23
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发表时间：
1991-07-01
影响因子：
3.3
通讯作者：
TSUBOI, M
中科院分区：
文献类型：
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作者：
IZAWA, T;KOMABAYASHI, T;TSUBOI, M
采用毛地黄皂苷透性脂肪细胞，研究腺苷酸环化酶（AC）与运动训练大鼠脂解的偶联。异丙肾上腺素-（IPR）刺激的透化细胞的脂解作用显着大于训练比对照组大鼠。在基本相同的条件下，在没有3-异丁基-1-甲基黄嘌呤的情况下，训练大鼠和对照大鼠的IPR刺激AC活性的剂量-反应曲线相似。然而，由IPR作为基础水平的百分比的刺激的效力在训练的大鼠中更大。AC活性和脂解在3-异丁基-1-甲基黄嘌呤的存在下，也显着大于在对照组大鼠训练。通过绘制log AC与脂解值的最小二乘分析表明，训练大鼠的回归系数约为对照大鼠的三倍。在对照组和训练组大鼠中，产生半数最大脂解反应所需的内源性环磷酸腺苷（cAMP）浓度分别为18.58和10.81 pmol.min-1.10（6）cells-1。因此，脂肪分解和AC活性之间存在着正相关关系，在训练大鼠中耦合更紧密。在响应外源性cAMP的脂解倾向于更大的训练比对照组大鼠，50 μ M和10 mM cAMP的差异是统计学上显着的。我们的研究结果支持了这样的概念，即在训练大鼠中增强脂肪分解的主要机制是cAMP远端的酶促步骤的活性增加。
Digitonin-permeabilized adipocytes were used to study the coupling of adenylate cyclase (AC) to lipolysis in exercise-trained rats. Isoproterenol- (IPR) stimulated lipolysis in permeabilized cells was significantly greater in trained than in control rats. Under essentially identical conditions, the dose-response curve for IPR stimulation of AC activity in the absence of 3-isobutyl-1-methylxanthine was similar in trained and control rats. However, the potency of stimulation by IPR as a percentage of the basal level was greater in trained rats. AC activity and lipolysis in the presence of 3-isobutyl-1-methylxanthine were also significantly greater in trained than in control rats. Least-squares analysis by plotting the log AC vs. lipolysis values showed that the regression coefficient was about three-fold greater in trained than in control rats. The concentration of endogenous adenosine 3',5'-cyclic monophosphate (cAMP) needed to produce a half-maximal lipolytic response was 18.58 and 10.81 pmol.min-1.10(6) cells-1 in control and trained rats, respectively. Thus a positive relationship existed between lipolysis and AC activity, with a tighter coupling in trained rats. Lipolysis in response to exogenous cAMP tended to be greater in trained than in control rats, and the difference was statistically significant for 50-mu-M and 10 mM cAMP. Our findings support the concept that the major mechanism of enhanced lipolysis in trained rats was an increase in the activity of enzymatic step(s) distal to cAMP.