This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Barazzoni, R. Articles by Guarnieri, G. Search for Related Content PubMed PubMed Citation Articles by Barazzoni, R. Articles by Guarnieri, G.

Moderate Caloric Restriction, But Not Physiological Hyperleptinemia Per Se, Enhances Mitochondrial Oxidative Capacity in Rat Liver and Skeletal Muscle—Tissue-Specific Impact on Tissue Triglyceride Content and AKT Activation

Clinica Medica (R.B., M.Z., A.B., G.B., L.V.-S., G.G.), Department of Clinical, Morphological and Technological Sciences, and Centro Servizi Polivalenti di Ateneo (CSPA)-Animal Facility (M.S.), University of Trieste, Trieste 34100, Italy

Address all correspondence and requests for reprints to: Rocco Barazzoni, M.D., Ph.D., Clinica Medica, University of Trieste, Ospedale Cattinara, Strada di Fiume 447, 34100 Trieste, Italy. E-mail: barazzon{at}units.it.

The study aimed at determining, in lean tissues from nonobese rats, whether physiological hyperleptinemia with leptin-induced reduced caloric intake and/or calorie restriction (CR) per se: 1) enhance mitochondrial-energy metabolism gene transcript levels and oxidative capacity; and 2) reduce triglyceride content. Liver and skeletal muscles were collected from 6-month-old Fischer 344 rats after 1-wk leptin sc infusion (0.4 mg/kg · d: leptin + 3-fold leptinemia vs. ad libitum-fed control) or moderate CR (–26% of those fed ad libitum) in pair-fed animals (CR). After 1 wk: 1) leptin and CR comparably enhanced transcriptional expression of mixed muscle mitochondrial genes (P < 0.05 vs. control); 2) CR independently increased (P < 0.05 vs. leptin-control) hepatic mitochondrial-lipooxidative gene expression and oxidative capacity; 3) hepatic but not muscle mitochondrial effects of CR were associated (P < 0.01) with increased activated insulin signaling at AKT level (P < 0.05 vs. leptin-control); 4) liver and muscle triglyceride content were comparable in all groups. In additional experiments, assessing time course of posttranscriptional CR effects, 3-wk superimposable CR (P < 0.05): 1) increased both liver and muscle mitochondrial oxidative capacity; and 2) selectively reduced muscle triglyceride content. Thus, in nonobese adult rat: 1) moderate CR induces early increments of mitochondrial-lipooxidative gene expression and time-dependent increments of oxidative capacity in liver and mixed muscle; 2) sustained moderate CR alters tissue lipid distribution reducing muscle but not liver triglycerides; 3) mitochondrial-lipid metabolism changes are tissue-specifically associated with hepatic AKT activation; 4) short-term physiological hyperleptinemia has no independent stimulatory effects on muscle and liver mitochondrial-lipooxidative gene expression. Increased lean tissue oxidative capacity could favor substrate oxidation over storage during reduced nutrient availability.

This article has been cited by other articles:

				C. Kolditz, M. Borthaire, N. Richard, G. Corraze, S. Panserat, C. Vachot, F. Lefevre, and F. Medale Liver and muscle metabolic changes induced by dietary energy content and genetic selection in rainbow trout (Oncorhynchus mykiss) Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2008; 294(4): R1154 - R1164. [Abstract] [Full Text] [PDF]

				A. Valle, R. Guevara, F. J. Garcia-Palmer, P. Roca, and J. Oliver Sexual dimorphism in liver mitochondrial oxidative capacity is conserved under caloric restriction conditions Am J Physiol Cell Physiol, October 1, 2007; 293(4): C1302 - C1308. [Abstract] [Full Text] [PDF]

				R. Barazzoni, A. Bernardi, F. Biasia, A. Semolic, A. Bosutti, M. Mucci, F. Dore, M. Zanetti, and G. Guarnieri Low fat adiponectin expression is associated with oxidative stress in nondiabetic humans with chronic kidney disease--impact on plasma adiponectin concentration Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2007; 293(1): R47 - R54. [Abstract] [Full Text] [PDF]