Functional potentiation of leptin-signal transducer and activator of transcription 3 signaling by the androgen receptor

Endocrinology. 2008 Dec;149(12):6028-36. doi: 10.1210/en.2008-0431. Epub 2008 Aug 14.

Abstract

Hypogonadism is associated with increased fat mass and dysregulation of metabolic homeostasis in men. Our previous study revealed that androgen receptor (AR)-null male mice (ARL-/Y) develop late-onset obesity and are leptin-resistant. The present study evaluated how hypothalamic AR contributes to central leptin-signal transducer and activator of transcription 3 (STAT3) signaling. We evaluated leptin action in wild-type and ARL-/Y mice, the anatomic co-relationship between AR and leptin signaling in the hypothalamus, and the effects of AR on leptin-mediated STAT3 transactivation and nuclear translocation. AR deletion in male mice results in a weaker leptin-induced suppression of food intake and body weight drop even before the onset of overt obesity. In wild-type male but not female mice, AR was highly expressed in various hypothalamic nuclei that also expressed the long-form leptin receptor (OBRB) and co-resided with OBRB directly in the arcuate neurons. In vitro, AR significantly enhanced STAT3-mediated transcription of leptin target genes including POMC and SOCS3. This effect relied on the AR N-terminal activation function-1 (AF-1) domain and was specific to AR in that none of the other sex steroid hormone receptors tested showed similar effects. AR enhanced the low concentrations of leptin-induced STAT3 nuclear translocation in vitro, and ARL-/Y mice receiving leptin had impaired STAT3 nuclear localization in the arcuate neurons. These findings indicate that AR in the hypothalamus functions as a regulator of central leptin-OBRB-STAT3 signaling and has a physiological role in energy homeostasis and metabolic regulation in male mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport / drug effects
  • Blotting, Western
  • Body Weight / drug effects
  • COS Cells
  • Cell Line
  • Chlorocebus aethiops
  • Eating / drug effects
  • Female
  • Immunohistochemistry
  • Leptin / pharmacology*
  • Male
  • Mice
  • Mice, Knockout
  • Microscopy, Confocal
  • Pro-Opiomelanocortin / metabolism
  • Receptors, Androgen / genetics
  • Receptors, Androgen / metabolism
  • Receptors, Androgen / physiology*
  • Receptors, Leptin / metabolism
  • STAT3 Transcription Factor / metabolism*
  • Signal Transduction / drug effects*
  • Signal Transduction / physiology
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins / metabolism
  • Transcriptional Activation / drug effects

Substances

  • Leptin
  • Receptors, Androgen
  • Receptors, Leptin
  • STAT3 Transcription Factor
  • Socs3 protein, mouse
  • Stat3 protein, mouse
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins
  • Pro-Opiomelanocortin