Steroid metabolism by the lung: conversion of dihydrotestosterone to 5 alpha-androstan-3 alpha, 17 beta-diol by rat lung tissue in vitro.

The potential of lung tissue of adult male rats metabolize dihydrotestosterone (DHT) in vitro was examined. Within 3 min, a homogenate of 100 mg lung tissue, cleared of blood by perfusion before homogenization, metabolized 90% of the [3H]DHT substrate. Appoximately 80% of the DHT was converted to 5 alpha-androstan- alpha, 17 beta-diol. The amount of 5 alpha-androstan-3 alpha, 17 beta-diol formed during a 5-min incubation increased linearly, with substrate concentrations ranging from 3.3 x 10(-8) to 3 x 10(-6) M. Thus, the capacity of rat lung tissue to metabolize DHT in vitro and the rate of 3 alpha-reduction of DHT are sufficiently great to consider the possibility that lung may be responsible for the rapid clearance of DHT from the circulation in this species.