Influence of Protein and Caloric Intake upon Spontaneous Tumor Incidence of the Anterior Pituitary Gland of the Rat

Abstract

The level of caloric intake and the proportion of protein in the diet was found to modify the incidence of spontaneous chromophobe adenomas of the anterior pituitary gland of the male rat. Three purified diets, differing only in the protein-calorie ratio, were employed. Each diet was provided throughout post-weaning life in ad libitum or in restricted but isocaloric amounts. Under ad libitum feeding conditions the highest incidence of chromophobe adenomas was found to be associated with the dietary group having the highest intake of food. Under restricted conditions tumor prevalence was directly related to the level of the protein component in the diet. Restriction in both caloric intake and protein intake depressed the incidence to the greatest extent. Among all six dietary groups, body weight of the rat early in life correlated directly with tumor prevalence of later life. In the ad libitum series, individuals of greater maximum body weight were more prone to anterior pituitary gland tumors than rats of lighter weight.