Apparent immunologic nonidentity of human placental and endometrial 17beta-estradiol dehydrogenase

Immunohistochemical techniques were used to search for the presence of 17beta-estradiol dehydrogenase activity in human endometrial and placental tissues, with the use of antibodies raised against highly purified human placental 17beta-estradiol dehydrogenase. Sensitivity and specificity of the antibodies were documented by radioimmunoassay and immunodiffusion on cellulose acetate. Although staining was consistently demonstrated in the syncytiotrophoblast layer of term placentas, in both cytoplasm and nuclei, no immunohistochemical reaction was observed in endometrial samples. These results support the contention that placental 17beta-estradiol dehydrogenase is immunologically dissimilar from the endometrial enzyme.