Hypothalamic NPY, AGRP, and POMC mRNA responses to leptin and refeeding in mice.
Food deprivation (FD) increases hypothalamic neuropeptide Y (NPY) and agouti-related protein (AGRP) mRNA levels and decreases proopiomelanocortin (POMC) mRNA levels; refeeding restores these levels. We determined the time course of changes in hypothalamic NPY, AGRP, and POMC mRNA levels on refeeding after 24 h FD in C57BL mice by in situ hybridization. After 24 h deprivation, mice were refed with either chow or a palatable mash containing no calories or were injected with murine leptin (100 microg) without food. Mice were perfused 2 or 6 h after treatment. Food deprivation increased hypothalamic NPY mRNA (108 +/- 6%) and AGRP mRNA (78 +/- 7%) and decreased hypothalamic POMC mRNA (-15 +/- 1%). Refeeding for 6 h, but not 2 h, was sufficient to reduce (but not restore) NPY mRNA, did not affect AGRP mRNA, and restored POMC mRNA levels to ad libitum control levels. Intake of the noncaloric mash had no effect on mRNA levels, and leptin administration after deprivation (at a dose sufficient to reduce refeeding in FD mice) was not sufficient to affect mRNA levels. These results suggest that gradual postabsorptive events subsequent to refeeding are required for the restoration of peptide mRNA to baseline levels after food deprivation in mice.
Swart
I
I
Program in Neuroscience, The Florida State University, Tallahassee, Florida 32306-4340, USA.
Jahng
J W
JW
Overton
J M
JM
Houpt
T A
TA
D054369:Agouti-Related Protein; D000818:Animals; D001823:Body Composition / Q000502:physiology; D001835:Body Weight / Q000187:drug effects; D004435:Eating / Q000502:physiology*; D002149:Energy Intake / Q000502:physiology; D005508:Food Deprivation / Q000502:physiology; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D007422:Intestines / Q000502:physiology; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009478:Neuropeptide Y / Q000096:biosynthesis*; D010812:Physical Stimulation; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis*; D014176:Protein Biosynthesis; D011506:Proteins; D012333:RNA, Messenger / Q000096:biosynthesis*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013649:Taste / Q000502:physiology
D054369:Agouti-Related Protein; C515199:Agrp protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D020738:Leptin; D009478:Neuropeptide Y; D011506:Proteins; D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin