| Abstract: | Rats aged 6, 12, 24, 36, and 52 weeks were subjected to social isolation for 4 days, while littermates housed in groups of six for the same period served as controls. The isolation treatment resulted in a 2-fold increase in the serum corticosterone level of all except the youngest animals in whom the hormone level was greater than 4 times that of their age-matched controls. Hepatic microsomal protein was highest in the 24-week-old rats and lowest in the rats aged 52 weeks. The levels of most of the enzymes measured were lowest in the 6- and 52-week-old animals. No significant differences in microsomal protein, cytochrome P450, epoxide hydrolase, UDPGA transferase, or glutathione transferase were observed between the isolated and control animals. The stress treatment increased aryl hydrocarbon hydroxylase levels of the rats aged 6, 36, and 52 weeks by 100%, 50%, and 33% respectively. The microsomes prepared from livers of isolated 6-week-old animals catalyzed the binding of significantly higher amounts of [3H]-benzo(a)pyrene to DNA than controls. |
