Fat Metabolism

Abstract

This review covers some aspects of fat metabolism which have not been discussed in detail in previous years. It has been difficult to ob tain foreign literature and therefore the review is incomplete. NERVOUS SYSTEM AND FAT METABOLISMRelation of the hypothalamus to fat metabolism.-Since 1940 when the symposium on the hypothalamus was published by the Association for Research in Nervous and Mental Diseases (1), many groups of investigators have made systematic attacks on the problem of hypo thalamic regulation of metabolism including that of fat. Hetherington & Ranson (2, 3, 4) have demonstrated conclusively in rats that care fully placed bilateral lesions in the ventromedial nuclei of the hypothal amus (injury to pituitary was avoided) produced promptly increase of appetite and subsequently extreme obesity. Removal of the pituitary provoked no obesity, and also did not prevent development of obesity following hypothalamic lesions. Even when sufficient time after hypo physectomy, eleven weeks, was allowed to elapse for atrophy of thy roid, adrenals, and gonads to develop, subsequent hypothalamic lesions were still followed by hyperphagia and obesity. These results have been confirmed in the monkey by Brooks, Lambert & Bard (5), in the dog by Heinbecker et at. (6) , and in the cat by Wheatley (7). Hetherington (4) has tried, in an extensive series of experiments, to localize the lesions which consistently result in obesity. He con cluded that cell groups of basal forebrain rostral to the ventromedial hypothalamic nucleus made little if any contribution to regulation of fat metabolism. Destruction of the ventromedial hypothalamic nucleus or its descending fibers in the brain stem was required to produce hyperphagia and obesity.That diffuse injuries to brain may disturb fat metabolism has been suggested by the effects of insufflation of air into ventricles of the dog. Schrade (8) observed that three to four hours after air injection the total blood fats were reduced in amount. Phospholipids, cholesterol, and neutral fats all decreased in concentration. The change in cho-333 Annu. Rev. Biochem. 1945.14:333-356. Downloaded from www.annualreviews.org by Massachusetts Institute of Technology (MIT) on 11/05/14. For personal use only. Quick links to online content Further ANNUAL REVIEWS