Conversion of circulating estrone sulfate to 17beta-estradiol by ovarian tumor tissue: a possible mechanism behind elevated circulating concentrations of 17beta-estradiol in postmenopausal women with ovarian tumors.
OBJECTIVE
Elevated serum levels of 17beta-estradiol (E2) are frequently found in postmenopausal women with ovarian tumors not classified as estrogen-producing. Conversion of circulating estrone sulfate (E1S) to E2 is one alternative way of E2 formation in target tissues in postmenopausal women. Our aim was to find out if conversion of circulating E1S to E2 by the tumor tissue could be a reason for elevated serum E2 levels in postmenopausal women with 'non-estrogen-producing' ovarian tumors.


METHODS
Serum E2 was measured in 12 postmenopausal women with 'non-estrogen-producing' ovarian tumors (nine benign, three malignant). Total hydrolysis of and [3H]E2 formation from [3H]E1S by the tumor tissue homogenates was studied in vitro.


RESULTS
Serum E2 showed significant positive correlations with total hydrolysis of and [3H]E2 formation from [3H]E1S in the total material as well as in the benign tumor subgroup. [3H]E2 formation was the most important independent variable.


CONCLUSIONS
Conversion of circulating E1S to E2 by the tumor tissue could be one important reason for elevated S-E2 levels in postmenopausal women with 'non-estrogen-producing' ovarian tumors.
Kirilovas
Dmitrijus
D
Department of Women's and Children's Health, Section of Obstetrics and Gynecology, Uppsala University Hospital, Uppsala, Sweden.
Schedvins
Kjell
K
Naessén
Tord
T
Von Schoultz
Bo
B
Carlström
Kjell
K
D004958:Estradiol / Q000097:blood / Q000378:metabolism*; D004970:Estrone / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000097:blood / Q000378:metabolism*; D017698:Postmenopause
D004970:Estrone; D004958:Estradiol; C017296:estrone sulfate