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Journal of Diabetes Research
Volume 2014, Article ID 765784, 9 pages
http://dx.doi.org/10.1155/2014/765784
Research Article

Insulin Increases Ceramide Synthesis in Skeletal Muscle

1Department of Physiology and Developmental Biology, 593 WIDB, Brigham Young University, Provo, UT 84602, USA
2Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA

Received 18 March 2014; Revised 15 April 2014; Accepted 22 April 2014; Published 18 May 2014

Academic Editor: Konstantinos Papatheodorou

Copyright © 2014 M. E. Hansen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aims. The purpose of this study was to determine the effect of insulin on ceramide metabolism in skeletal muscle. Methods. Skeletal muscle cells were treated with insulin with or without palmitate for various time periods. Lipids (ceramides and TAG) were isolated and gene expression of multiple biosynthetic enzymes were quantified. Additionally, adult male mice received daily insulin injections for 14 days, followed by muscle ceramide analysis. Results. In muscle cells, insulin elicited an increase in ceramides comparable to palmitate alone. This is likely partly due to an insulin-induced increase in expression of multiple enzymes, particularly SPT2, which, when knocked down, prevented the increase in ceramides. In mice, 14 days of insulin injection resulted in increased soleus ceramides, but not TAG. However, insulin injections did significantly increase hepatic TAG compared with vehicle-injected animals. Conclusions. This study suggests that insulin elicits an anabolic effect on sphingolipid metabolism in skeletal muscle, resulting in increased ceramide accumulation. These findings reveal a potential mechanism of the deleterious consequences of the hyperinsulinemia that accompanies insulin resistance and suggest a possible novel therapeutic target to mitigate its effects.