Siddle K, Hales C N
Biochem J. 1974 Jul;142(1):97-103. doi: 10.1042/bj1420097.
The relationship between cyclic AMP content and lipolysis, as measured by glycerol formation, was studied in isolated rat fat-cells. Inhibition of lipolysis by insulin in the presence of a low concentration of adrenaline was accompanied by little or no lowering of cyclic AMP content, measured after 15min incubation. The time-course of cyclic AMP content after addition of adrenaline showed that the effect of insulin in lowering cyclic AMP content measured after 2-5min was gradually lost over the next hour, mainly because of the fall in cyclic AMP content after an early peak in the presence of adrenaline alone. There was a 44% loss of immunoreactive insulin, from an initial concentration of 0.3nm, during a 1h incubation with fat-cells. Insulin did not affect partitioning of cyclic AMP between cells and incubation medium. When the correlation between cyclic AMP content and rate of lipolysis was investigated for a wide range of adrenaline concentrations, it was found that the lowering of cyclic AMP content by insulin was much less than that required to account for the amount of inhibition of lipolysis. It is concluded that inhibition of adrenaline-stimulated lipolysis by insulin involves factors in addition to a decrease in intracellular cyclic AMP concentration.
在分离的大鼠脂肪细胞中，研究了以甘油生成量衡量的环磷酸腺苷（cAMP）含量与脂肪分解之间的关系。在低浓度肾上腺素存在的情况下，胰岛素对脂肪分解的抑制作用伴随着孵育15分钟后cAMP含量几乎没有降低或根本没有降低。添加肾上腺素后cAMP含量的时间进程表明，胰岛素在2 - 5分钟后测量时降低cAMP含量的作用在接下来的一小时内逐渐消失，这主要是因为在仅存在肾上腺素时早期达到峰值后cAMP含量下降。在与脂肪细胞孵育1小时期间，免疫反应性胰岛素从初始浓度0.3nM损失了44%。胰岛素不影响cAMP在细胞与孵育培养基之间的分配。当研究广泛的肾上腺素浓度范围内cAMP含量与脂肪分解速率之间的相关性时，发现胰岛素降低cAMP含量的程度远低于解释脂肪分解抑制量所需的程度。结论是，胰岛素对肾上腺素刺激的脂肪分解的抑制作用涉及细胞内环磷酸腺苷浓度降低之外的其他因素。
