Metabolic hydroxylations of trans-stilbene.

1. A study was made of the hydroxylation of trans-stilbene in rabbits, guinea pigs and mice, as well as by rabbit liver microsomes. 2. In the rabbit in vivo, trans-stilbene is converted into 4-hydroxy-,4,4'-dihydroxy-,3-hydroxy-4-methoxy-and 4-hydroxy-3-methoxy-stilbene, and hydroxylation plays a more significant role in the metabolism of trans-stilbene than has previously been reported. 3. Investigation of the hydroxylation of 4-hydroxystilbene in the rabbit in vivo demonstrated its ready conversion into 4,4'-dihydroxystilbene and established its intermediacy in the formation of this compound and the methylated analogues of 3,4-dihydroxystilbene. 4. Hydroxylation of trans-stilbene in the guinea pig was found to follow a pattern similar, both qualitatively and quantitatively, to that in the rabbit. 5. Studies in the mouse revealed only limited yields of 4,4'-dihydroxystilbene. 6. Studies of the hydroxylation of trans-stilbene and 4-hydroxystilbene by rabbit liver microsomes located two of the reactions that occur with these compounds in vivo. 7. Work with a solubilized liver-microsomal preparation provided evidence that ;stilbene hydroxylase' activity is not completely lost on solubilization, thus allowing for future microsomal enzyme-isolation studies.