The effect of heat stress on the induced hepatic drug metabolizing system in rats

Abstract

The activity of the hepatic oxidative drug metabolizing system has been investigated in an experimentally-induced heat stress animal model pretreated with phenobarbitone. Female rats, unacclimatized and untrained were pretreated for 3 days with phenobarbitone as the inducing agent for the drug metabolizing systems. On the fourth day, they were restrained and exposed to an ambient temperature of 40 degrees C. One hour after acute exposures to such conditions, the activities of hepatic cytochrome P450, cytochrome b5 and NADPH cytochrome c reductase were significantly decreased in the induced animal model. Further, cytochrome P450 isozymes observed by SDS-gel electrophoresis were significantly decreased. In addition, the hypnotic effect of pentobarbitone was significantly increased. It is concluded that the activity of the hepatic oxidative drug metabolizing enzymes was decreased in induced drug metabolism systems exposed to heat stress conditions.

Effect of Heat Stress on the Expression of HSP70, UCP3 and CYP450 Genes in Liver; Longissimus Dorsi and Semitendinosus Muscle of Growing Pigs

“…Stress is a critical player in the regulation of most CYPs that could modify their activity and gene expression (Daskalopoulos et al, 2012). Decreased activity in rats (Damanhouri, 2002) and liver expression of this enzyme in mid-lactation of dairy cows due to the HS exposure (McCracken et al, 2015) were reported. Acute exposure of mouse to 40-42°C increased the expression of CYP3A in liver and promoted hepatocyte proliferation, but the exposure to 44-46°C inhibited proliferation and promoted apoptosis of hepatocytes (Li et al, 2012).…”