Iritani N, Fukuda H, Tashiro S, Ikeda Y
J Biochem. 1982 Aug;92(2):569-74. doi: 10.1093/oxfordjournals.jbchem.a133965.
The insulin binding to hepatic plasma membranes, erythrocytes and adipocytes of 1-, 2-, and 9-month-old rats was measured by using [125I]insulin. When rats were fed a fat-free diet, the capacities of the insulin bindings significantly decreased with aging, whereas the dissociation constants were not altered. The capacities of 9-month-old rats were decreased to about half those of 1-month-old rats for plasma membranes, and about one-third for erythrocytes and adipocytes. On the other hand, the plasma insulin levels tended to be high with increasing age at 9-10 a.m., while the levels were even more elevated at 8-9 p.m. and not altered by aging. The insulin binding capacities were increased by feeding the fat-free diet to rats adapted to a stock diet and the increases were reduced with aging. The insulin binding capacities correlated well with the magnitudes of induction of lipogenic enzymes as reported previously [Iritani, N., Fukuda, H., & Fukuda, E. (1981) Biochim. Biophys. Acta 665, 636]. Therefore, it is suggested that insulin binding is implicated in age-dependent alterations of lipogenic enzyme induction.
采用[125I]胰岛素测定1月龄、2月龄和9月龄大鼠肝细胞膜、红细胞和脂肪细胞的胰岛素结合情况。当给大鼠喂食无脂饮食时，胰岛素结合能力随衰老显著降低，而解离常数未发生改变。9月龄大鼠肝细胞膜的结合能力降至1月龄大鼠的约一半，红细胞和脂肪细胞的结合能力降至约三分之一。另一方面，上午9 - 10点时血浆胰岛素水平随年龄增长有升高趋势，而晚上8 - 9点时水平升高更明显，且不受衰老影响。给适应普通饲料的大鼠喂食无脂饮食可增加胰岛素结合能力，且这种增加随衰老而减少。胰岛素结合能力与脂肪生成酶诱导程度密切相关，如之前报道[入谷，N.，福田，H.，&福田，E.（1981年）生物化学与生物物理学学报665, 636]。因此，提示胰岛素结合与脂肪生成酶诱导的年龄依赖性改变有关。
