Anorexigenic substances and voluntary food intake in the pig

Abstract

The urine of pigs contains a substance with an anorexigenic effect when injected into pigs or rats. When injected into rats or pigs on ad libitum feeding a urine extract caused a reduction in food intake only when the extract had been obtained from the urine of satiated pigs, and not from hungry pigs. The pig urinary anorexigen there-fore appears to be similar in nature to the anorexigen extracted from rat urine. Like rat urinary anorexigen, its anorexigenic effect is largely dose dependent and it is soluble in distilled water. Rats injected with plasma from satiated pigs showed an anorexigenic reaction but injection of plasma from hungry pigs had no effect on food intake. The possible role of these anorexigenic substances in the control of voluntary food intake in the pig is discussed.