In vitro binding of progesterone by the human endometrium during the menstrual cycle and by hyperplastic, atrophic, and carcinomatous endometrium

Abstract

The specific progesterone-binding capacity of 34 endometrium specimens, representing normal menstrual cycle endometrium, atrophic and hyperplastic endometrium, and endometrial carcinoma, was studied. by an equilibrium dialysis method developed for this purpose. To measure the extent of the nonspecific binding by endometrial proteins, the samples were also dialyzed against human albumin solution. The highest binding rates were observed during the late proliferative and secretory phases of the menstrual cycle. Atrophic endometrium appeared to be completely devoid of specific progesterone-binding capacity. Hyperplastic endometrium showed varying binding rates, but no correlation was observed with the degree of hyperplasia as judged by morphologic criteria. In endometrial carcinoma, the highest binding rates were comparable with those shown by hyperplastic or proliferative endometrium, whereas two of the specimens were completely inactive. There seemed to be no correlation between the degree of differentiation of the tumor and the progesterone-binding capacity. The clinical implications of the method are discussed.