Effect of cholecystokinin octapeptide on body temperature in the rat.

Abstract
The C-terminal octapeptide of cholecystokinin (CCK-8) injected into the lateral ventricle of rats produced a lowering of body temperature. CCK-8 potentiated pentobarbital-induced hypothermia, but not the ethanol one. Thyrotropin releasing hormone (TRH) and prostaglandin E2 (PGE2) antagonized the hypothermic effect of CCK-8. Non-sulfated CCK-8 was ineffective in lowering body temperature, indicating sulfated tyrosine in the CCK molecule is indispensable for its hypothermic action. Caerulein possesses less activity compared with CCK-8.