Changes in cholecystokinin receptor binding in rat brain after food deprivation

Levels of cholecystokinin (CCK) receptor binding in 7 brain regions were measured in two groups of adult male rats using iodinated CCK-8 as the radioligand. One group was deprived of food for 72 h prior to sacrifice and the other group had food available ad libitum. The deprivation resulted in a 13% decrease in body weight. In comparison to the ad libitum rats, the deprived group had a significantly lower level of CCK receptor binding in the olfactory bulb, and significantly higher levels of binding in the caudate nucleus, hypothalamus and midbrain. No significant differences were noted in samples of cerebral cortex, hippocampus or hindbrain. These results demonstrate that levels of CCK receptor binding can be altered by an acute change in the metabolic state of the animal.