Expression of aromatase cytochrome P450 protein and messenger ribonucleic acid in human endometriotic and adenomyotic tissues but not in normal endometrium. Biol. Reprod

To determine whether local estrogen production takes place in endometriotic or adenomyotic tissues, in eutopic endometri-um from patients with endometriosis or adenomyosis, and in normal endometrium, tissue specimens were examined by im-munohistochemistry, catalytic activity, and mRNA expression for aromatase cytochrome P450 (P450,..). P4500.. was immuno-histochemically localized in the cytoplasm of glandular cells of endometriotic and adenomyotic tissues, and of eutopic endo-metrium from patients with the respective diseases, whereas es-trogen receptors and progesterone receptors were localized in the nuclei of the glandular cells and stroma. Aromatase activity in the microsomal fraction of adenomyotic tissues was inhibited by the addition of danazol, aromatase inhibitors, and anti-hu-man placental P450,aro monoclonal antibody (mAb3-2C2) in a manner similar to such inhibition in other human tissues. Re-verse transcription polymerase chain reaction and Southern blot analysis also revealed P450r, mRNA in these tissues. However, neither P450,r,, protein activity nor mRNA was detected in en-dometrial specimens obtained from normal menstruating wom-en with cervical carcinoma in situ but without any other gyne-cological disease. These results suggest that at a local level, en-dometriotic and adenomyotic tissues produce estrogens, which may be involved in the tissue growth through interacting with the estrogen receptor.