Species difference in intestinal drug metabolising enzymes in mouse, rat and hamster and their inducibility by masheri, a pyrolysed tobacco product.

Activities of several drug metabolising enzymes in the small intestine were investigated in Swiss mice, Sprague Dawley rats and Syrian Golden Hamsters fed 10% masheri, a pyrolysed tobacco product, in diet, for 20 months. The basal levels of enzymes in proximal (PI), medium (MI) and distal (DI) parts of the intestine in the three species were similar. However, the levels of cytochrome P-450, benzo(a) pyrene hydroxylase (B(a)OH) and glutathione S-transferase (GST) were highest in hamsters followed by rat and mice. Upon treatment with masheri, significant induction of cytochrome P-450 and B(a)PH was observed in PI and DI of all the three species. However, GSH and GST was depleted upon masheri treatment in all the three species again only in proximal and distal parts of the intestine. Thus increase in activating enzymes together with depletion in GSH-GST system upon exposure could be an important factor in the susceptibility of the small intestine to hazardous xenobiotic exposure.