The urine Hepatic Detox profile is used to detect significant toxicant exposure and the activity of the primary pathway of Phase II detoxification. Hepatic exposure to a vast array of toxicants causes concomitant up-regulation of both cytochrome P-450 isozymes and the glucuronic acid pathway. In humans this pathway ends with D-glucaric acid; therefore elevated levels of D-glucaric acid in urine indirectly indicate up-regulation of Phase I detoxification as a result of exposure to xenobiotics.
Mercapturic acids are final conjugated products of Phase II detoxification and include sub functional xenobiotics that have been conjugated with glutathione and/or L-cysteine prior to excretion. Urinary levels of Mercapturic acids are indicative of the quantitative degree of activity or capabilities of Phase II detoxification. Subordinate levels of Mercapturic acids are consistent with inadequate levels of glutathione and/or cysteine or insufficient glutathione-S-transferase (GST) activity. The clinical utility of the Hepatic Detox profile is that it portrays the balance or imbalance of Phase I and Phase II detoxification processes.