Importance of prepyriform cortex in food-intake response of rats to amino acids.

LEUNG, PHILIP M.-B., AND QUINTON R. ROGERS. Importance of prepyriform cortex in food-intake response of rats to amino acids. Am. J. Physiol. 221(3): 929-935. 197 1 .-Bilateral electrolytic lesions were placed in the prepyriform cortex of male 230to 250-g rats and their food intake as affected by amino acid imbalance, deficiency, and excessive protein was examined. All rats with such lesions and groups of intact controls were fed in turn a basal, imbalanced (with either threonine or isoleucine as the limiting amino acid), or deficient diet (devoid of either threonine or isoleucine), and finally the lowor high-protein (670 or 75% casein) diet. No change in food intake was observed in rats fed the control diet after the placement of the lesions. However, animals with lesions in certain areas of the anterior prepyriform cortex showed a significant increase in food intake as compared to the intact controls fed the imbalanced or deficient diets, but the decrease in food intake was still evident in rats fed the high-protein diet. Intact animals select a protein-free diet over an imbalanced diet, whereas the rats with lesions in certain areas of the anterior prepyriform cortex chose the imbalanced diet over the protein-free diet. The altered choice between the basal and the imbalanced or deficient diets of the rats with lesions in the critical prepyriform cortical areas suggests that these areas are involved in the regulation of food intake of rats fed amino acid-imbalanced or deficient diets.