INTERMEDIARY METABOLISM IN DIABETES MELLITUS

Abstract

An important problem in fat metabolism is the determination of the chemical mechanism by which the energy of fat becomes available for muscular work.There are two conceivable mechanisms: (1) direct ox&&on, in which the oxidation of fatty acids is initiated and completed in the muscles, and (2) indirect oxidation, in which there is a preliminary partial oxidation by the liver of fatty acids; diffusible substrates are formed which are completely oxidized in the muscles.The possibility that both processes are operative at the same time must also be considered.Differences of opinion arose particularly over the second hypothesis and became formulated into three alternative hypotheses: (a) Successive /3 oxidation.Fats are partially oxidized in the liver to ketone bodies plus a a-carbon compound (acetic acid).Successive p oxidation may under some conditions proceed from both ends of the fatty acid chain (w oxidation).In this case one of the end-products of the oxidation is a dicarboxylic acid.(b) Multiple alternate oxidation.Fats are partially oxidized in the liver to ketone bodies only.(c) Fat to carbohydrate.Fats are partially oxidized by the liver to carbohydrates as well as ketones.These theories have recently been discussed in detail by Stadie (1940).The hypothesis of jl oxidation of fatty acids was originally founded upon the work of Knoop (1904) and Dakin (1909), who