Influence of a Protein-Free Diet on the Immediate and Latent Effects of Stilbestrol

¹ From the Bureau of Biological Research and Department of Zoology, Rutgers University, New Brunswick, New Jersey

The absence of protein from the diet of stilbestrol-treated rats modified, largely quantitatively the response to the hormone. Stilbestrol, per se, induced a body weight loss which was greater in the protein-depleted than in the protein-fed animal. Recovery on an adequate protein diet, after withdrawal of the hormone permitted an immediate recouping of body weight losses, whereas animals on the protein-deficient diet did not recover body weight losses. Stilbestrol administration increased excretion of nitrogen indirectly by restriction of food intake. This nitrogen loss was augmented by protein depletion. The marked retention of nitrogen by animals recovering on an adequate diet was more pronounced in the treated animal but rats continued on the protein-deficient diet maintained a negative nitrogen balance. The absence of protein from the diet diminished the anticatabolic influence of stilbestrol on total liver protein. Recovery on the basal diet allowed the repletion of liver protein but further decreases in liver protein concentration followed recovery on the deficient diet. A marked increase in the concentration of liver fat appeared concomitantly with the progressive depletion of liver protein in both treated and untreated groups.