The metabolism of cis- and trans-decalin.

1. The metabolism of cis- and trans-decalin in the rabbit has been investigated. 2. Both hydrocarbons were oxidized to racemic secondary alcohols and excreted as ether glucuronides in amounts equal to about 60% of the dose administered. The principal glucuronides were isolated as triacetyl methyl esters and as sodium salts. 3. cis-Decalin gave rise mainly to (+/-)-cis-cis-2-decalol, together with a little cis-trans-2-decalol, and trans-decalin mainly to (+/-)-trans-cis-2-decalol and a small amount of trans-trans-2-decalol. 4. These results suggest that biological oxidation of the decalins does not occur via a free-radical mechanism. An attempt is made to explain why racemic alcohols are obtained, rather than the more typical optically active products of enzymic reaction, and a mechanism is proposed. It is suggested that enzymes similar to steroid hydroxylases are involved.