Hypothalamic neuropeptide Y disturbances in the obese (cp/cp) JCR:LA corpulent rat.
Regional hypothalamic neuropeptide Y (NPY) concentrations were compared between cp/cp JCR:LA corpulent rats, which were grossly obese, hyperphagic, and hyperinsulinemic, and lean (+/+) controls. In freely fed cp/cp rats, NPY levels in the arcuate nucleus (ARC) were 31% higher than in lean rats (p less than 0.001). In lean rats, chronic food restriction significantly raised NPY levels by 22% in the ARC (p less than 0.05) and by 44% in the dorsomedial nucleus (DMH; p less than 0.05). By contrast, food-restricted cp/cp rats showed no change in the ARC, but NPY levels rose in the DMH (by 36%; p less than 0.05) and ventromedial nucleus (31%; p less than 0.05). Increased NPY levels in the ARC, the major site of hypothalamic NPY synthesis, suggests increased NPYergic activity in cp/cp rats; given the central actions of NPY, this could contribute to hyperphagia, obesity, and hyperinsulinemia in this syndrome. Abnormal NPY responses to food deprivation further suggest dysregulation of NPY in cp/cp rats.
Williams
G
G
Department of Medicine, University of Liverpool, Canada.
Shellard
L
L
Lewis
D E
DE
McKibbin
P E
PE
McCarthy
H D
HD
Koeslag
D G
DG
Russell
J C
JC
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000737:chemistry; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D004302:Dorsomedial Hypothalamic Nucleus / Q000737:chemistry; D004435:Eating; D007031:Hypothalamus / Q000737:chemistry*; D007328:Insulin / Q000097:blood; D008297:Male; D009478:Neuropeptide Y / Q000032:analysis*; D009765:Obesity / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011922:Rats, Mutant Strains; D014697:Ventromedial Hypothalamic Nucleus / Q000737:chemistry
D001786:Blood Glucose; D007328:Insulin; D009478:Neuropeptide Y