Conversion of estrone to estradiol and estradiol to estrone in postmenopausal women.

The conversion of estrone to estradiol and metabolism of estradiol to estrone have been measured in postmenopausal women to examine factors that influence these conversions. Transfer constants for the conversion of estrone to estradiol and estradiol to estrone were not significantly correlated with age (r = -.01 and r = .1, respectively) or subjects' percentage of ideal body weight (r = -.25 and r = -.22, respectively). There was a significant negative correlation between the transfer constants for the conversion of estradiol to estrone and plasma levels of dehydroepiandrosterone sulphate (r = -.45, P less than .05) but not plasma levels of progesterone. Transfer constants for the conversion of estrone to estradiol and metabolism of estradiol to estrone in women with breast or endometrial disease were similar to values in normal women, but metabolism of estradiol to estrone was elevated in two women with primary biliary cirrhosis.