Central (ICV) leptin injection increases bone formation, bone mineral density, muscle mass, serum IGF-1, and the expression of osteogenic genes in leptin-deficient ob/ob mice

Document Type

Article

Publication Date

2011

Abstract

Both central and peripheral leptin administrations reduce body weight, food intake, and adiposity in ob/ob mice. In this study we compared effects of intracerebroventricular (ICV) and subcutaneous (SC) administration of leptin on bone metabolism in the appendicular and axial skeleton and adipose tissue gene expression and determined the effects of ICV leptin on bone marrow gene expression in ob/ob mice. In experiment 1, leptin (1.5 or 0.38μg/d) or control was continuously injected ICV for 12 days. Gene expression analysis of femoral bone marrow stromal cells showed that expression of genes associated with osteogenesis was increased after ICV injection, whereas those associated with osteoclastogenesis, adipogenesis, and adipocyte lipid storage were decreased. In experiment 2, leptin was injected continuously ICV (0.0 or 1.5μg/d) or SC (0.0 or 10μg/d) for 12 days. In both experiments, regardless of mode of administration, leptin decreased body weight, food intake, and body fat and increased muscle mass, bone mineral density, bone mineral content, bone area, marrow adipocyte number, and mineral apposition rate. Serum insulin was decreased, whereas serum osteocalcin, insulin-like growth factor 1, osteoprotegerin, pyridinoline, and receptor activator of nuclear factor κB ligand concentrations were increased. In experiment 2, expression of genes in adipose tissue associated with apoptosis, lipid mobilization, insulin sensitivity, and thermogenesis was increased, whereas expression of genes associated with cell differentiation and maturation was decreased regardless of mode of administration. Thus ICV injection of leptin promotes expression of pro-osteogenic factors in bone marrow, leading to enhanced bone formation in ob/ob mice. Copyright © 2011 American Society for Bone and Mineral Research.

Publication Title

Journal of Bone and Mineral Research

Volume

26

Issue

8

First Page

1710

Last Page

1720

Comments

This article was published in Journal of Bone and Mineral Research, Volume 26, Issue 8, Pages 1710-1720.

The published version is available at http://dx.doi.org/10.1002/jbmr.406.

Copyright © 2011 ASBMR.

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