S. Bi et al., A role for NPY overexpression in the dorsomedial hypothalamus in hyperphagia and obesity of OLETF rats, AM J P-REG, 281(1), 2001, pp. R254-R260
Citations number
46
Categorie Soggetti
Physiology
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
Otsuka Long-Evans Tokushima Fatty (OLETF) rats lacking CCK-A receptors are
hyperphagic, obese, and diabetic. We have previously demonstrated that thes
e rats have a peripheral satiety deficit resulting in increased meal size.
To examine the potential role of hypothalamic pathways in the hyperphagia a
nd obesity of OLETF rats, we compared patterns of hypothalamic neuropeptide
Y (NPY), proopiomelanocortin (POMC), and leptin receptor mRNA expression i
n ad libitum-fed Long-Evans Tokushima (LETO) and OLETF rats and food-restri
cted OLETF rats that were pair-fed to the intake of LETO controls. Pair fee
ding OLETF rats prevented their increased body weight and elevated levels o
f plasma insulin and leptin and normalized their elevated POMC and decrease
d NPY mRNA expression in the arcuate nucleus. In contrast, NPY expression w
as upregulated in the dorsomedial hypothalamus (DMH) in pair-fed OLETF rats
. A similar DMH NPY overexpression was evident in 5-wk-old preobese OLETF r
ats. These findings suggest a role for DMH NPY upregulation in the etiology
of OLETF hyperphagia and obesity.