Leptin regulation of prepro-orexin and orexin receptor mRNA levels in the hypothalamus.
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.
López
M
M
Department of Physiology, University of Santiago de Compostela, Santiago de Compostela, Spain.
Seoane
L
L
García
M C
MC
Lago
F
F
Casanueva
F F
FF
Señarís
R
R
Diéguez
C
C
D000818:Animals; D004435:Eating / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D005215:Fasting / Q000502:physiology; D005508:Food Deprivation / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D020738:Leptin / Q000494:pharmacology* / Q000502:physiology; D008297:Male; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D011498:Protein Precursors / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide / Q000235:genetics* / Q000502:physiology
D047908:Intracellular Signaling Peptides and Proteins; D020738:Leptin; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D011498:Protein Precursors; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide