Fat-deficiency disease of rats. The storage of fat in the fat-starved rat

BuRR &. BURR [1930], to whom we owe the first description of the fat-deficiency disease of rats, originally attributed the curative effect of the essential un- saturated fatty acids to their power of promoting fat synthesis. According to these observers: 'These small emaciated animals on the fat-free diet consume as much food daily as their larger fat-containing controls yet this food is burned and none is used in growth and fat synthesis. On the addition of the unsaturated fatty acid growth is resumed and a normal amount of subcutaneous and visceral fat is found in the cured animal at autopsy. Therefore fat synthesis is dependent upon the presence in the tissues or blood stream of a certain minimum quantity of the essential fatty acids. What percentage of the growth observed is due to storage of fat and what percentage is due to increase in other compounds (protein and carbohydrate) is not yet known.' Subsequent investigations of the respiratory quotient, at various stages of the fat-deficiency disease carried out by Burr and his colleagues indicated that the formation of fat from carbohydrate must be taking place [Wesson & Further confirmation of the synthesis of fatty acid from carbohydrate was supplied by an investigation of the rate of synthesis of pho'spholipin in the organs of the fat-starved rat. The rate of turnover of phosphorus in the liver, kidney and muscle of the fat-starved rat was as high as in those in which the fat-free diet had been supplemented with methyl linoleate; indeed in muscle tissue, the rate of phospholipin synthesis was significantly higher in those animals which had been fat-starved