Differential role of melanocortins in mediating leptin's central effects on feeding and reproduction

John G. Hohmann, Thomas H. Teal, Donald K. Clifton, James Davis, Victor J. Hruby, Guoxia Han, Robert A. Steiner

Research output: Contribution to journalArticle

71 Scopus citations

Abstract

Leptin serves as a humoral link coupling the status of energy reserves to the functional activity of the reproductive system. Leptin is thought to act through melanocortinergic pathways in the brain to regulate ingestive behaviors; however, whether melanocortins mediate leptin's actions on the neuroendocrine-reproductive axis is unknown. We tested this hypothesis first by determining whether the effects of leptin on feeding behavior and reproduction in the ob/ob mouse could be blocked by the melanocortin receptor (MC-R) antagonist SHU9119 and second, by examining the effects of the MC-R agonist MTII on feeding and the endocrine-reproductive system. Administered by intracerebroventricular injections, leptin inhibited food intake, raised plasma gonadotropin levels, and increased seminal vesicle weights compared with controls; SHU9119 (intracerebroventricularly) attenuated leptin's effects on food intake and body weight but did not alter leptin's stimulatory effect on the reproductive axis. MTII (intracerebroventricularly and intraperitoneally) decreased food intake and increased body temperature compared with controls but had no effect on the reproductive-endocrine axis. These results suggest that although leptin acts centrally through melanocortinergic pathways to inhibit ingestive behaviors and stimulate metabolism, leptin's activational effect on the reproductive axis is likely to be mediated by other, unknown neuroendocrine circuits.

Original languageEnglish (US)
Pages (from-to)R50-R59
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume278
Issue number1 47-1
DOIs
StatePublished - Jan 2000

Keywords

  • MTII
  • Obesity
  • Proopiomelanocortin
  • SHU9119
  • Thermogenesis
  • α-melanocyte-stimulating hormone

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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