title: Effects of betamethasone on the in vitro and in vivo 2-hydroxylation of biphenyl in the rat.
abstract: The in vitro addition of betamethasone to rat liver microsomes caused a concentration-dependent stimulation of biphenyl 2-hydroxylation. At a 100 microM concentration of betamethasone, the formation of 2-hydroxybiphenyl was increased by approximately 4-fold in microsomes from 28-day-old rats and 10-fold in liver microsomes from 5-day-old rats. The steroid had little or no effect on the hydroxylation of biphenyl in the 3- or 4-position except at the highest concentration tested (1 mM), where a 20-30% inhibition was observed. The ip injection of 0.01 to 10 mumol of betamethasone to 5-day-old rats had little or no effect on the total body metabolism of 0.01 to 3.5 mumol of biphenyl-2-3H to 2-hydroxybiphenyl as measured by 3H2O formation. Although betamethasone had no effect on the 2-hydroxylation of biphenyl in the intact rat, this reaction was stimulated 4- to 9-fold by the addition of 100 microM betamethasone to hepatocyte monolayer cultures.
mesh_terms: D000375:Aging; D000818:Animals; D001623:Betamethasone / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006900:Hydroxylation; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D051381:Rats
chemical_list: D001623:Betamethasone; D001713:Biphenyl Compounds; D003577:Cytochrome P-450 Enzyme System; C010574:biphenyl