Intermediary metabolism of adipic acid
Abstract
Adipic acid is absorbed and metabolized by normal metabolic processes by the rat. When radioactive adipic acid was fed to fasted rats, metabolic products identified as urea, glutamic acid, lactic acid, β-ketoadipic acid, and citric acid, as well as adipic acid, were found in the urine.
The presence of β-ketoadipic acid provides some evidence that adipic acid is metabolized by β-oxidation in much the same fashion as fatty acids. Further evidence is provided by the appearance of succinate in the urine of rats fed radioactive adipic acid (1-C14) and injected with malonic acid.
The presence of radioactive acetyl-γ-phenyl-α-aminobutyric acid after feeding γ-phenyl-α-aminobutyric acid and C14-labeled adipic acid provides very strong evidence that acetate is a metabolite of adipic acid.
Radioactive glycogen was isolated following feeding of glucose and radioactive adipic acid.
Some of the metabolic products found in the urine are most certainly not direct degradation products of adipic acid, 3.g., urea, but contain radioactive carbon, derived via carbon dioxide from adipic acid. This has been indicated by feeding tests with radioactive carbon dioxide followed by the isolation of traces of some of the same metabolic products in the urine.