Human placenta mitochondrial aromatase--fact or artifact

The suggestion has been made that the aromatase system from human placenta converting testosterone to estradiol-17 beta is localized to some extent in the mitochondrial fraction in addition to its microsomal origin. By comparing the characteristics of the "mitochondrial" aromatase with certain particularities of other mitochondrial or microsomal enzymes, especially those functioning in steroid hydroxylation, the conclusion has been reached that the mitochondrial and the microsomal aromatases are one and the same. Thus, in response to ultrasound treatment and in response to the addition of specific cofactors, the mitochondrial aromatase showed all the characteristics attributed to microsomal enzymes and was indistinguishable from the microsomal aromatase.