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Exp Cell Res. 2008 Jul 1;314(11-12):2249-56. doi: 10.1016/j.yexcr.2008.04.003. Epub 2008 Apr 12.

Insulin regulates leptin secretion from 3T3-L1 adipocytes by a PI 3 kinase independent mechanism.

Author information

1
Department of Molecular Genetics, The Rockefeller University, New York, NY 10021, USA.

Abstract

To better define the molecular mechanisms underlying leptin release from adipocytes, we developed a novel protocol that maximizes leptin production from 3T3-L1 adipocytes. The addition of a PPARgamma agonist to the Isobutylmethylxanthine/Dexamethasone/Insulin differentiation cocktail increased leptin mRNA levels by 5-fold, maintained insulin sensitivity, and yielded mature phenotype in cultured adipocytes. Under these conditions, acute insulin stimulation for 2 h induced a two-fold increase in leptin secretion, which was independent of new protein synthesis, and was not due to alterations in glucose metabolism. Stimulation with insulin for 15 min induced the same level of leptin release and was blocked by Brefeldin A. Inhibiting PI 3-kinase with wortmannin had no effect on insulin stimulation of leptin secretion. These studies show that insulin can stimulate leptin release via a PI3K independent mechanism and provide a cellular system for studying the effect of insulin and potentially other mediators on leptin secretion.

PMID:
18501893
PMCID:
PMC2997521
DOI:
10.1016/j.yexcr.2008.04.003
[Indexed for MEDLINE]
Free PMC Article

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