PROTEIN-TURNOVER RATES OF 2 HUMAN-SUBJECTS DURING AN UNASSISTED CROSSING OF ANTARCTICA

During the Austral summer of 1992-3, two men, MS and RF, walked 2300 k m across Antarctica in 96 d, unassisted by other men, animals or machi nes, During the journey they ate freeze-dried rations, towed on sledge s, that contained an average of 21.3 MJ/d of which 56.7% was fat, 35.5 % carbohydrate and 7.8% protein (98.8 g), Despite this high energy int ake both men lost more than 20 kg in body weight due to their extremel y high energy expenditures, Studies of protein turnover using [N-15]gl ycine by the single-dose end-product method were made before, during a nd after the journey, and these demonstrated considerable differences in the metabolic responses of the two men to the combined stresses of exercise, cold and undernutrition, However, both men maintained high a nd relatively stable levels of protein synthesis during the expedition despite the great exertion and the onset of considerable debilitation , This stability indicates the vital physiological function of protein synthesis.