Leptin Regulation of Prepro-orexin and Orexin Receptor mRNA Levels in the Hypothalamus

• DOI: 10.1006/bbrc.2000.2245
• Publication Date: 2002-10-06T21:58:25Z
• Authors: Miguel López; Luisa Seoane; María del Carmen ...; Francisca Lago; Felipe F. Casanueva; Rosa Señarís; Carlos Diéguez
• Keywords: Leptin; Male; Receptors, Neuropeptide; 2. Zero hunger; 0301 basic medicine; Orexins; Neuropeptides; Hypothalamus; Intracellular Signaling Peptides and Proteins; Fasting; Rats; Receptors, G-Protein-Coupled; Rats, Sprague-Dawley; Eating; 03 medical and health sciences; Gene Expression Regulation; Orexin Receptors; Animals; RNA, Messenger; Protein Precursors; Food Deprivation; In Situ Hybridization

The aim of this study was to determine the effects of leptin treatment on prepro-orexin and orexin receptor expression in the rat hypothalamus. Adult male rats, food-deprived for 48 and 72 h, were treated one time with vehicle or leptin (10 microg, icv). Prepro-orexin mRNA content was measured by semiquantitative RT-PCR, Northern blot, and in situ hybridization; orexin receptor 1 and 2 mRNA content was quantified by Northern blot and/or semiquantitative RT-PCR. Our results indicate that leptin inhibits a fasting-induced increase in prepro-orexin mRNA and orexin receptor 1 mRNA levels in the rat hypothalamus, while orexin receptor 2 mRNA levels were unchanged in all situations evaluated. These data provide direct evidence for an additional mechanism of adaptation of the hypothalamus to food deprivation and for a new effect of leptin in the regulation of food intake.