The Ah regulatory gene product. Survey of nineteen polycyclic aromatic compounds' and fifteen benzo[a]pyrene metabolites' capacity to bind to the cytosolic receptor

The capacity of 19 polycyclic aromatic compounds and 15 benzoa]pyrene metabolites to displace $\text{1,6-}{}^3\text{H}\text{]2,3,7,8-}\text{tetrachlorodibenzo}\text{-p-}\text{dioxine}\text{(}{}^3\text{H]Tcdd}\text{)}$ from the mouse liver cytosolic Ah receptor was examined. We compared our data with various parameters taken from previously published results: the capacity of seven polycyclic hydrocarbons to induce aryl hydrocarbon hydroxylase (AHH) activity in human cell cultures, the capacity of 10 polycyclic hydrocarbons to induce azo dye N-demethylase activity in rat liver, the capacity of 6 polycyclic hydrocarbons to shorten zoxazolamine paralysis times in the intact rat, and the capacity of 15 benzoa]pyrene metabolites to induce AHH activity in rat hepatoma H-4-II-E cultures. An excellent correlation is seen between the capacity to displace the radioligand from the Ah receptor and the capacity to induce these monooxygenase activities. Differences in the rate of cellular uptake and formation of alkali-extractable metabolites of dibenzoa,h]anthracene, 3-methylcholanthrene, and benzoa]anthracene in Hepa-1 mouse hepatoma cell cultures do not account for differences in the capacity of these three polycyclic hydrocarbons to displace ³H]TCDD from the Ah receptor.