RELATIONSHIPS OF DIET TO THE DURATION OF SURVIVAL, BODY WEIGHT AND COMPOSITION OF HYPOPHYSECTOMIZED RATS1

Abstract

Between 60% and 70% of rats fed purified diets ad libitum after surgical removal of the hypophysis survived for exptl. periods of at least 88 and 112 days. Only 10% of comparable rats offered laboratory chow survived beyond 45 days and none more than 63 days. The long survival of hypophysectomized rats fed the purified rations was not due to the fine particle size of the purified rations nor to their lack of undigestible crude fiber. Those hypophysectomized rats which survived for long periods increased considerably in body wt. and, apparently, synthesized considerable protein during the growth process. Tail growth was observed, individual caudal vertebrae lengthened, and the epiphyses of the caudal vertebrae did not close. Hypophysectomized rats which had been maintained on purified rations for 112 days, during which time they had doubled their body wt., had a slightly lower protein content but, otherwise, did not differ greatly in their carcass analyses from intact rats fed purified rations for comparable periods.[long dash].