Steroid metabolism by a species of Pseudomonas. II. Direct evidence for the breakdown of testosterone.

It has recently been shown in our laboratories that a soil microorganism, Pseudomonas No. 7, can grow in pure culture in the presence of testosterone as the sole source of carbon (1). Manometrically, oxygen uptake and carbon dioxide evolut,ion were noted with this st,eroid as substrate. At the end of the incubation period, definite amounts of testosterone had disappeared. These results were interpreted to mean that this steroid was metabolized by the cells. In this communication, labeled testosterone was employed, and definitive data will be presented for the unequivocal utilization of this complex molecule by bacteria.’