Dissociation of paraventricular NPY release and plasma corticosterone levels in rats under food deprivation.
Extracellular neuropeptide Y (NPY) in the vicinity of the paraventricular nucleus (PVN) as well as NPY concentrations in the PVN were measured in rats under ad libitum feeding and 2-day and 10-day food deprivation. Plasma corticosterone levels were not changed by 2-day food deprivation but were increased by subsequent refeeding. In contrast, the extracellular NPY levels were increased by 2-day food deprivation and were decreased rapidly by refeeding. The NPY concentrations were also increased and increased further by refeeding. On the other hand, plasma corticosterone levels were elevated by 10-day food deprivation and were decreased by subsequent refeeding. The extracellular NPY levels were also increased by food deprivation and decreased gradually after refeeding. However, the postprandial levels were still elevated when plasma corticosterone levels were returned to the basal levels. The NPY concentrations were also increased and increased further by refeeding. The amount of food intake after refeeding was positively correlated with the extracellular NPY levels. It is concluded that extracellular NPY levels in the PVN do not necessarily covariate with plasma corticosterone levels in rats under food deprivation.
Yoshihara
T
T
Department of Physiology, Hokkaido University School of Medicine Sapporo, Japan.
Honma
S
S
Katsuno
Y
Y
Honma
K
K
D000818:Animals; D003345:Corticosterone / Q000097:blood*; D005508:Food Deprivation / Q000502:physiology*; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D009478:Neuropeptide Y; D003345:Corticosterone