Urinary excretion of C4--C10-dicarboxylic acids and antiketogenic properties of adipic acid in ketogenic-stimulated rats due to diabetes, long-chain and short-chain monocarboxylic acids.

The urinary excretion of C4--C10-dicarboxylic acids (succinic, adipic, suberic and sebacic acids) and the antiketogenicity of adipic acid have been studied in ketogenic-stimulated rats in three biochemically different states: diabetes, fat-feeding (long-chain monocarboxylic acids) and feeding of hexanoic acid (short-chain monocarboxylic acid). In diabetic rats urinary excretions of adipic and suberic acids were elevated before the rise in urinary excretions of 3-hydroxybutyric acid, i.e. before ketosis appeared. In severe diabetic ketosis sebacic acid was below normal values, whereas the excretion of succinic acid was unaltered. Rats, in which ketosis was provoked by hexanoic acid, had preketotic high urinary excretions of adipic and succinic acids. After ketosis the excretions of succinic acid declined again whereas the excretion of adipic acid rose further, together with that of suberic acid. Moreover, when rats which were ketotic due to treatment with long-chain triacylglycerol or hexanoic acid received 500 mg of adipic acid the urinary excretion of succinic acid rose significantly. However, no changes in succinic acid excretion were seen in diabetic ketotic rats treated with the same amount of adipic acid. Exogenously administered adipic acid was strongly antiketogenic towards ketosis caused by long-chain or short-chain monocarboxylic acids, but had no effect on diabetic ketosis.