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Nutrition/Metabolism Laboratory, Cancer Research Institute, New England Deaconess Hospital/Harvard Medical School, Boston, MA 02215
Changes in protein content and function were investigated in male Sprague-Dawley Crl:Cd rats that were either fasted, consumed a diet containing 1.5 g fat/100 g initial body weight per day or received ad libitum an 85% carbohydrate, minimal nitrogen diet. Fasted rats became moribund after 910 days and were both hypoglycemic and hypoketonemic. In contrast, rats fed the fat-only and high carbohydrate, minimal nitrogen diets survived the 28-day study period. Although rats consuming the high carbohydrate, minimal nitrogen diet lost less body weight and nitrogen than either fasted animals or rats receiving the fat-only diet, they also had a loss of delayed hypersensitivity recall to tuberculin antigen and a 55% decrease in plasma essential amino acid concentrations. Rats fed the fat-only diet maintained delayed hypersensitivity recall and near normal concentrations of plasma essential amino acids despite a greater loss of body nitrogen than was observed in terminally fasted animals. Plasma albumin concentrations and total liver protein content showed comparable decreases in rats consuming the two incomplete diets. We concluded that nonprotein calories prolong survival in the rat and fat or predominantly glucose calories are sufficient at preventing mortality. However, the source or quantity of nonprotein calories consumed during periods of protein deprivation can markedly alter individual tissue protein status and function.
KEY WORDS: protein status tuberculin antigens
1 Supported in part by grants GM-22691, GM-24206 and GM-24401, awarded by the National Institute of General Medical Science, AM-17456, awarded by the National Institute of Arthritis, Metabolism and Digestive Diseases, and RR-00591, awarded by the Research Resources Division, National Institutes of Health, DHHS, L.L.M. was supported in part by a grant from the Center for Nutritional Research Charitable Trust. This is article #689 from the Cancer Research Institute, New England Deaconess Hospital.
2 To whom reprint requests should be sent: Cancer Research Institute, New England Deaconess Hospital, 194 Pilgrim Rd., Boston, MA 02215.
Manuscript received 5 January 1981.