Adrenomedullin expression in the human endometrium

Immunohistochemical studies were performed using a specific antibody to human adrenomedullin (AM) to determine its presence and cellular localization in the human endometrium, in the different phases of the menstrual cycle, and in the postmenopausal period. Specimens were obtained from 21 patients who underwent abdominal hysterectomy for various reasons. The endometrium had no pathological lesion in all cases. In the early and mid proliferative phases of the menstrual cycle, no immunostaining for AM was noted in the endometrium. AM immunostaining in the endometrium became apparent in the late proliferative phase. The staining intensity of AM in the endometrium became more abundant in the secretory phase. No appreciable difference in the staining intensity of AM in the endometrium was noted among early, mid, and late secretory phases. Immunostaining for AM was evident in both the epithelial and stromal compartments of the endometrium. In the postmenopausal endometrium, there was intense immunostaining for AM only in the stromal compartment. This is the first study to demonstrate the expression of AM in the endometrium in relation to the menstrual cycle. The results obtained suggest the participation of AM in the growth and differentiation of the endometrium.