Title:
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Increased hepatic insulin sensitivity in mice lacking inhibitory leptin receptor signals
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Author:
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Tom, Robby Zachariah; Sjögren, Rasmus J. O.; Vieira, Elaine; Glund, Stephan; Iglesias-Gutiérrez, Eduardo; García-Roves, Pablo M. (Pablo Miguel); Myers Jr, Martin G.; Björnholm, Marie
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Other authors:
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Universitat de Barcelona |
Abstract:
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Leptin regulates food intake and energy expenditure by activating the long form of the leptin receptor (LepRb). Leptin also regulates glucose homeostasis by improving whole-body insulin sensitivity, but the mechanism remains undefined. Leptin action is mediated by phosphorylation of several tyrosine residues on LepRb. LepRb-Tyr985 plays an important role in the attenuation of LepRb signaling. We determined the contribution of LepRb-Tyr985-mediated signals to leptin action on insulin sensitivity using LepRb-Tyr985 mutant mice (l/l mice). Glucose tolerance and whole-body insulin-mediated glucose utilization were determined in wild-type (+/+) and l/l mice. Glucose tolerance was unaltered between female +/+ and l/l mice but enhanced in the male l/l mice. Serum insulin concentration was decreased at baseline and 15 min after a glucose injection in female l/l vs. +/+ mice (P < 0.05) but unaltered in the male l/l mice. However, basal and insulin-stimulated glucose transport in isolated soleus and extensor digitorum longus muscle was similar between +/+ and l/l mice, indicating skeletal muscle insulin sensitivity in vitro was not enhanced. Moreover, euglycemic-hyperinsulinemic clamps reveal hepatic, rather than peripheral, insulin sensitivity is enhanced in female l/l mice, whereas male l/l mice display both improved hepatic and peripheral insulin sensitivity. In conclusion, signals emanating from leptin receptor Tyr985 control hepatic insulin sensitivity in both female and male l/l mice. Lack of LepRb-Tyr985 signaling enhances whole-body insulin sensitivity partly through increased insulin action on the suppression of hepatic glucose production. |
Subject(s):
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-Insulina -Malalties del fetge -Leptina -Ratolins (Animals de laboratori) -Insulin -Liver diseases -Leptin -Mice (Laboratory animals) |
Rights:
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(c) Association for the Study of Internal Secretions, 2011
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Document type:
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Article Article - Published version |
Published by:
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Association for the Study of Internal Secretions
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