Document Detail


The response of skeletal muscle to leptin.
MedLine Citation:
PMID:  11145919     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
There is now compelling evidence that, in addition to signaling to the central nervous system (CNS), leptin also exerts its metabolic effects acting directly on peripheral tissues. It has been demonstrated by in vivo and in vitro studies, that leptin increases glucose and fatty acid metabolism in skeletal muscle. These direct leptin effects are supported by the presence of the long form of the leptin receptor, considered to be capable of performing intracellular signaling, in peripheral tissues, including skeletal muscle. The exposure of soleus muscle to supra-physiological leptin concentrations stimulate the activity of both the pyruvate-dehydrogenase (PDH) complex and Krebs cycle. This could be due to a direct stimulation of PDH and krebs cycle by leptin or a consequence of an indirect effect of this hormone activating the mitochondrial uncoupling process. In addition, in soleus and extensor digitorum longus (EDL) muscles, leptin and insulin had opposite effects on lipid metabolism, with leptin favoring lipid oxidation and insulin favoring lipid storage as triglycerides (TG). The leptin effects on free fatty acid (FFA) oxidation were more pronounced in soleus than in EDL. The differences in response of soleus compared with that of EDL was probably due to differences in fiber type composition and metabolic characteristics. It has been demonstrated that leptin reduces the TG content of skeletal. When tissue TG content is severely depleted by hyperleptinemia in normal rats, there is a dramatic increase in insulin sensitivity. This lipopenic effect of leptin may protect from the development of insulin resistance and diabetes in animals. In humans, obesity is also associated with an increase in insulin resistance and the development of Type II diabetes, however, contrary to rats and mice, there is abundance of leptin, indicating a state of resistance to this hormone in humans. Future studies are necessary to investigate the reasons why lean subjects seem to respond properly to endogenous leptin while obese ones don't. The understanding of the putative direct leptin signaling pathway in skeletal muscle could be an important step towards the utilization of leptin or a leptin receptor agonist as therapeutic tools to treat obesity and its related metabolic disorders.
Authors:
R B Ceddia; W N William; R Curi
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review     Date:  2001-01-01
Journal Detail:
Title:  Frontiers in bioscience : a journal and virtual library     Volume:  6     ISSN:  1093-4715     ISO Abbreviation:  Front. Biosci.     Publication Date:  2001 Jan 
Date Detail:
Created Date:  2001-01-18     Completed Date:  2001-02-01     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9709506     Medline TA:  Front Biosci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  D90-7     Citation Subset:  IM    
Affiliation:
Department of Physical Education, Universidade Federal Fluminense, Outeiro de São João Batista - S/No, Centro, Niterói, Rio de Janeiro, Brasil, 24020-150. roceddia@openlink.com.br
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MeSH Terms
Descriptor/Qualifier:
Animals
Carrier Proteins / genetics,  metabolism
Fatty Acids / metabolism
Glucose / metabolism
Humans
Insulin / metabolism
Insulin Resistance
Leptin / deficiency,  metabolism*,  pharmacology
Muscle, Skeletal / metabolism*
Obesity / genetics,  metabolism
Receptors, Cell Surface*
Receptors, Leptin
Triglycerides / metabolism
Chemical
Reg. No./Substance:
0/Carrier Proteins; 0/Fatty Acids; 0/Leptin; 0/Receptors, Cell Surface; 0/Receptors, Leptin; 0/Triglycerides; 0/leptin receptor, human; 11061-68-0/Insulin; 50-99-7/Glucose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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