Food restriction selectively increases hypothalamic orexin-B levels in lactating rats.

Abstract

Orexins are hypothalamic peptides implicated in the regulation of ingestive and other behaviours. Here we investigated prepro-orexin expression and hypothalamic orexin-A and -B levels in lactating rats, which display marked hyperphagia, with or without food restriction for 2 days or treatment with bromocriptine, which inhibits milk production and thus reduces the energy losses of lactation. Neither prepro-orexin gene expression nor hypothalamic orexin-A peptide levels were changed in any of these lactating groups compared with age-matched virgin controls. However, hypothalamic orexin-B levels were significantly higher in lactating rats that were food-restricted for 2 days (P<0.05) compared with non-lactating controls and with lactating rats that were either freely-fed or bromocriptine-treated. Thus, food restriction superimposed on lactation selectively increases hypothalamic orexin-B levels, suggesting that orexin-A and -B may be differentially released or cleared. Changes in orexin-B availability may influence physiological activities other than energy homeostasis, perhaps inducing arousal.

• Authors: X J Cai, R Denis, R G Vernon, J C Clapham, S Wilson, J R Arch, G Williams
• Journal: Regulatory peptides (Regul Pept) Vol. 97 Issue 2-3 Pg. 163-8 (Mar 02 2001) ISSN: 0167-0115 [Print] Netherlands
• PMID: 11164952 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Intracellular Signaling Peptides and Proteins
• Neuropeptides
• Orexins
• RNA, Messenger

Topics

• Animals
• Energy Intake
• Female
• Hypothalamus (metabolism)
• Intracellular Signaling Peptides and Proteins
• Lactation
• Neuropeptides (genetics, metabolism)
• Orexins
• Pregnancy
• RNA, Messenger (genetics, metabolism)
• Rats
• Rats, Wistar