The liver and fat metabolism

THE outstanding evidence of the importance of the liver in fat metabolism is the intense accumulation of fat which occurs in this organ in widely varying experi- mental and pathological conditions. Known observations however do not at present provide any adequate reason for this fat accumulation. The desaturation hypothesis of Leathes [1925], based on the work of Leathes and Meyer-Wedell [1909] and of Hartley [1909], presents an attractive suggestion of the reasons why fat may be transported to the liver, for apart from the desaturation of the fatty acids themselves it serves to connect the metabolism of glycerides with that of liver phosphatides. In the last three years work in this laboratory has been directed towards an attempt to obtain further evidence on the function of the liver in fat metabolism, and part of this work has referred in particular to the desaturation theory. The results of these investigations [Channon et al. 1934, 1, 2,] together with those of other wQrkers discussed in the former paper, leave us reluctant to accept that part of the hypothesis which is concerned with desaturation until more positive evidence in its favour is acquired. On the other hand, although the investigations of the French school and of many other workers seem to suggest that the phosphatides of tissues and in particular those of the liver may be essential constituents of living cells-"l'element constant" of The fact that the percentage of liver phosphatide usually falls when fat infiltration occurs is an example of such a variation. Further, the extensive work of Best and collaborators [cf. Best, 1934] shows the remarkable effect of small amounts of choline in prevention and cure of fatty livers produced by various experimental conditions. Although the effect of choline may be exercised in manyways, one possible means is through the metabolism of choline-containing phosphatides.