Central administration of insulin suppresses food intake in chicks

Neurosci Lett. 2007 Aug 16;423(2):153-7. doi: 10.1016/j.neulet.2007.07.004. Epub 2007 Jul 22.

Abstract

Although the orexigenic action of peptide hormones such as ghrelin and growth hormone releasing peptide is different between chickens and mammals, the anorexigenic action of peptide hormones is similar in both species. For example, central administration of peptide hormones such as leptin, cholecystokinin or glucagon has been shown to suppress food intake behavior in chickens and mammals. Central administration of insulin suppresses food intake in mammals. However, the anorexigenic action of insulin in chickens has not yet been identified. In the present study, we investigated the effects of central administration of insulin on food intake in chicks. Intracerebroventricular administration of insulin in chicks significantly suppressed food intake. Central administration of insulin significantly upregulated mRNA levels of proopiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART) and corticotropin-releasing factor (CRF), but did not influence mRNA levels of neuropeptide Y and agouti-related protein in the hypothalamus. These results suggest that alpha-melanocyte stimulating hormone (alpha-MSH, an anorexigenic peptide from the post-translational cleavage of POMC), CART and CRF are involved in the anorexigenic action of insulin in chicks. Furthermore, central administration of alpha-MSH or CART significantly suppressed food intake. In addition, alpha-MSH significantly upregulated CRF mRNA expression, suggesting that the anorexigenic action of alpha-MSH is mediated by CRF. Our findings demonstrate that insulin functions in chicks as an appetite-suppressive peptide in the central nervous system and suggest that this anorexigenic action is mediated by CART, alpha-MSH and CRF.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Appetite Regulation / physiology*
  • Brain / drug effects*
  • Brain / physiology
  • Chickens
  • Corticotropin-Releasing Hormone / biosynthesis
  • Corticotropin-Releasing Hormone / drug effects
  • Dose-Response Relationship, Drug
  • Eating / drug effects*
  • Injections, Intraventricular
  • Insulin / administration & dosage*
  • Male
  • Melanocyte-Stimulating Hormones / biosynthesis
  • Melanocyte-Stimulating Hormones / drug effects
  • Nerve Tissue Proteins / biosynthesis
  • Nerve Tissue Proteins / drug effects
  • Pro-Opiomelanocortin / biosynthesis
  • Pro-Opiomelanocortin / drug effects
  • RNA, Messenger / analysis
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Insulin
  • Nerve Tissue Proteins
  • RNA, Messenger
  • cocaine- and amphetamine-regulated transcript protein
  • Pro-Opiomelanocortin
  • Melanocyte-Stimulating Hormones
  • Corticotropin-Releasing Hormone