Ahrén B, Månsson S, Gingerich R L, Havel P J
Department of Medicine, Lund University, Malmö, Sweden.
Am J Physiol. 1997 Jul;273(1 Pt 2):R113-20. doi: 10.1152/ajpregu.1997.273.1.R113.
Mechanisms regulating circulating leptin are incompletely understood. We developed a radioimmunoassay for mouse leptin to examine the influence of age, dietary fat content, and fasting on plasma concentrations of leptin in the background strain for the ob/ob mouse, the C57BL/6J mouse. Plasma leptin increased with age [5.3 +/- 0.6 ng/ml at 2 mo (n = 23) vs. 14.2 +/- 1.6 ng/ml at 11 mo (n = 15), P < 0.001]. Across all age groups (2-11 mo, n = 160), log plasma leptin correlated with body weight (r = 0.68, P < 0.0001), plasma insulin (r = 0.38, P < 0.001), and amount of intra-abdominal fat (r = 0.90, P < 0.001), as revealed by magnetic resonance imaging. Plasma leptin was increased by a high-fat diet (58% fat for 10 mo) and reduced by fasting for 48 h. The reduction of plasma leptin was correlated with the reduction of plasma insulin (r = 0.43, P = 0.012) but not with the initial body weight or the change in body weight. Moreover, the reduction in plasma leptin by fasting was impaired by high-fat diet. Thus plasma leptin in C57BL/6J mice 1) increases with age or a high-fat diet; 2) correlates with body weight, fat content, and plasma insulin; and 3) is reduced during fasting by an action inhibited by high-fat diet and related to changes of plasma insulin.
调节循环中瘦素的机制尚未完全明确。我们开发了一种针对小鼠瘦素的放射免疫分析法，以研究年龄、饮食脂肪含量和禁食对ob/ob小鼠的背景品系C57BL/6J小鼠血浆瘦素浓度的影响。血浆瘦素随年龄增加而升高[2月龄时为5.3±0.6 ng/ml（n = 23），11月龄时为14.2±1.6 ng/ml（n = 15），P < 0.001]。在所有年龄组（2 - 11月龄，n = 160）中，血浆瘦素对数与体重（r = 0.68，P < 0.0001）、血浆胰岛素（r = 0.38，P < 0.001）以及腹部脂肪量（r = 0.90，P < 0.001）相关，磁共振成像显示了这一点。高脂饮食（10个月含58%脂肪）可使血浆瘦素升高，禁食48小时则使其降低。血浆瘦素的降低与血浆胰岛素的降低相关（r = 0.43，P = 0.012），但与初始体重或体重变化无关。此外，高脂饮食会削弱禁食导致的血浆瘦素降低。因此，C57BL/6J小鼠的血浆瘦素：1）随年龄增长或高脂饮食而增加；2）与体重、脂肪含量和血浆胰岛素相关；3）在禁食期间因高脂饮食抑制的作用而降低，且与血浆胰岛素的变化有关。
