The adipokine leptin mediates muscle- and liver-derived IGF-1 in aged mice.

The adipokine leptin mediates muscle- and liver-derived IGF-1 in aged mice. Exp Gerontol. 2015 Jul 25; Authors: Hamrick MW, Dukes A, Arounleut P, Davis C, Periyasamy-Thandavan S, Mork S, Herberg S, Johnson MH, Isales CM, Hill WD, Otvos L, Belin de Chantemèle EJ Abstract Muscle- and liver-derived IGF-1 play important roles in muscle anabolism throughout growth and aging. Yet, prolonged food restriction is thought to increase longevity in part by lowering levels of IGF-1, which in turn reduces the risk for developing various cancers. The dietary factors that modulate IGF-1 levels are, however, poorly understood. We tested the hypothesis that the adipokine leptin, which is elevated with food intake and suppressed during fasting, is a key mediator of IGF-1 levels with aging and food restriction. First, leptin levels in peripheral tissues were measured in young mice fed ad libitum, aged mice fed ad libitum, and aged calorie-restricted (CR) mice. A group of aged CR mice were also treated with recombinant leptin for 10days. Later, aged mice fed ad libitum were treated with saline (VEH) or with a novel leptin receptor antagonist peptide (Allo-aca) and tissue-specific levels of IGF-1 were determined. On one hand, recombinant leptin induced a three-fold increase in liver-derived IGF-1 and a two-fold increase in muscle-derived IGF-1 in aged, CR mice. Leptin also significantly increased serum growth hormone levels in the aged, CR mice. On the o...
Source: Experimental Gerontology - Category: Geriatrics Authors: Tags: Exp Gerontol Source Type: research