ANDROGEN RECEPTOR CONTENT IN HUMAN ENDOMETRIUM

Human endometrium changes morphologically and biochemically during the various phases of the menstrual cycle, influenced by not only estroge ns and progesterone, but probably also by androgens. The purpose of th is study was to investigate the androgen receptor (AR) content in huma n endometrium and myometrium and its significance. AR immunocytochemis try was performed on 30 paraffin-embedded uterine sections of pre-meno pausal women who were scheduled for hysterectomy because of benign gyn aecologic abnormalities. AR receptor content was seen in all cell type s of the human endometrium and myometrium and was cyclic dependent. AR immunostaining of stromal and smooth muscle cells was more profound t han AR staining of glandular cells. There was more AR expression in th e proliferative phases than in the secretory phases; in the late secre tory phase there was no immunostaining in any of the cell types. AR ex pression is primarily under androgenic control. Inside the cell testos terone may be Sa-reduced to dihydrotestosterone (DHT). Due to local co mpetition between testosterone and the excess of progesterone in the s ecretory phase for the same iso-enzyme Su-reductase, the level of DHT will be diminished in the late secretory phase. If AR synthesis in end ometrium would be DHT dependent, the virtual disappearance of DHT woul d explain the lack of AR expression in the late secretory phase. Wheth er the cyclic pattern of AR expression is merely an epiphenomenon to p rogesteron production, or whether androgens play a causal role in the cyclic modulation of endometrium is subject to further research.