Enhancement of acetaminophen-induced chronic hepatotoxicity in spontaneously diabetic torii (SDT) rats.

Some patients encounter hepatotoxicity after repeated acetaminophen (APAP) dosing even at therapeutic doses. In the present study, we focused on the diabetic state as one of the suggested risk factors of drug-induced liver injury in humans and investigated the contribution of accelerated gluconeogenesis to the susceptibility to APAP-induced hepatotoxicity using an animal model of type 2 diabetes patients. Sprague-Dawley (SD) rats and spontaneously diabetic torii (SDT) rats were each given APAP at 0 mg/kg, 300 and 500 mg/kg for 35 days by oral gavage. Plasma and urinary glutathione-related metabolites, liver function parameters, and hepatic glutathione levels were compared between the non-APAP-treated SDT and SD rats and between the APAP-treated SDT and SD rats. Hepatic function parameters were not increased at either dose level in the APAP-treated SD rats, but were increased at both dose levels in the APAP-treated SDT rats. Increases in hepatic glutathione levels attributable to the treatment of APAP were noted only in the APAP-treated SD rats. There were differences in the profiles of plasma and urinary glutathione-related metabolites between the non-APAP-treated SD and SDT rats and the plasma/urinary endogenous metabolite profile after treatment with APAP in the SDT rats indicated that hepatic glutathione synthesis was decreased due to accelerated gluconeogenesis. In conclusion, SDT rats were more sensitive to APAP-induced chronic hepatotoxicity than SD rats and the high susceptibility of SDT rats was considered to be attributable to lowered hepatic glutathione levels induced by accelerated gluconeogenesis.

Enhancement of acetaminophen-induced chronic hepatotoxicity in restricted fed rats: a nonclinical approach to acetaminophen-induced chronic hepatotoxicity in susceptible patients.

Acetaminophen (APAP) is a commonly used and effective analgesic and antipyretic agent. However, some patients encounter hepatotoxicity after repeated APAP dosing at therapeutic doses. In the present study, we focused on the nutritional state as one of the risk factors of APAP-induced chronic hepatotoxicity in humans and investigated the contribution of undernourishment to susceptibility to APAP-induced chronic hepatotoxicity using an animal model mimicking undernourished patients. Rats were divided into 2 groups: the ad libitum fed (ALF) and the restricted fed (RF) rats and were assigned to 3 groups (n = 8/group) for each feeding condition. The animals were given APAP at 0, 300 and 500mg/kg for 99 days under each feeding condition. Plasma and urinary glutathione-related metabolites and liver function parameters were measured during the dosing period and hepatic glutathione levels were measured at the end of the dosing period. In the APAP-treated ALF rats hepatic glutathione levels were increased and hepatic function parameters were not changed, but in the APAP-treated RF rats hepatic glutathione levels were decreased at 500mg/kg and hepatic function parameters were increased at 300 and 500mg/kg. Moreover the urinary endogenous metabolite profile after long-term treatment with APAP in the ALF and RF rats was similar to that in human non-responders and responders to APAP-induced chronic hepatotoxicity, respectively. In conclusion, the RF rats were more sensitive to APAP-induced chronic hepatotoxicity than the ALF rats and were considered to be a useful model to estimate the contribution of the nutritional state of patients to APAP-induced chronic hepatotoxicity.