Steroid Metabolism by the Lung: Conversion of Dihydrotestosterone to 5α-Androstan-3α,17β-Diol by Rat Lung Tissue in Vitro

The potential of lung tissue of adult male rats to 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. Approximately 80% of the DHT was converted to 5α-androstan-3α,17β-diol. The amount of 5α-androstan- 3α,17β-diol formed during a 5-min incubation increased linearly, with substrate concentrations ranging from 3.3 × 10^-8 to 3 × 10^-6 M. Thus, the capacity of rat lung tissue to metabolize DHT in vitro and the rate of 3α-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.