IN VITRO INTERCONVERSION OF 16-C14-ESTRONE AND 16-C14-ESTRADIOL-17β BY ERYTHROCYTES FROM NORMAL SUBJECTS AND FROM SUBJECTS WITH A DEFICIENCY OF RED CELL GLUCOSE-6-PHOSPHATE DEHYDROGENASE ACTIVITY*

Abstract

The presence of an estradiol-17[beta] dehydrogenase in human red cells is confirmed. The enzyme is TPN dependent. It is coupled with the glucose-6-phosphate dehydrogenase for the transformation of estrone to estradiol-17[beta]. The thermolability and the pH optimum of the enzyme in intact cells has been determined. The red cells of subjects with glucose-6-phosphate deficiency have a marked but not complete decrease of the transformation, indicating that the interconversion of estrone and estradiol-17[beta] is related to the activity of the hexose monophosphate shunt. The physiological importance of the red cell estradiol-17[beta] dehydrogenase remains to be determined.