[Concentration of progesterone receptor in human endometrium with normal menstrual cycle, endometriosis or endometrial carcinoma (author's transl)].

By means of dextran-coated charcoal assay, the capacity of various endometrial cytosol preparation for specific binding of 3H-progesterone was determined. After sucrose gradient ultracentrifugation progesterone-binding components with sedimentation coefficients of 8S and 5S were found. Especially, 8S binding component tended to be saturated and highly specific for progesterone. And its dissociation constant and studies of competition with various unlabeled steroids revealed no significant difference between normal and abnormal endometrium. This 8S receptor in normal endometrium with regular menstrual cycle revealed cyclic changes in functional layer. It was extremely high at late proliferative and early secretary phase, but in basal layer, it was low and revealed no cyclic changes. In endometriosis binding capacities of 8S receptors from the lesions were detected as almost same values, but in some lesions 8S receptors were not detected. In endometrial carcinoma it depended on the degree of differentiation of the tumor. It was high in well differentiated form, and low in undifferentiated form. On well differentiated carcinoma, it was decreased markedly with administration of much gestagen. The other 5S macromolecule was consisted of plasma corticosteroid-binding globulin (plasma CBG) and/or some CBG-like component.