Response of hepatic drug-metabolizing enzymes to immobilization stress in rats of various ages.

The effects of acute two-hour immobilization stress in hepatic microsomal drug-metabolizing enzyme activities, liver and blood serum zinc and copper levels, content of vitamin C in adrenals, were studied in rats of three age categories (4, 12, 24 months old). Immobilization stress resulted in marked reduction in the concentrations of vitamin C in adrenals of all age categories. In stressed animals, the activities of microsomal aniline hydroxylase, p-nitroanisol 0-demethylase, and the hepatic concentrations of microsomal protein were significantly increased in young 4-month-old rats, especially. In these rats increased levels of zinc in blood serum and copper in the liver, were seen. The levels of zinc and copper in older rats after immobilization stress were apparently unchanged. Age-dependent decrease in the activities of hepatic microsomal monooxygenases and adrenal vitamin C content in control rats were observed.