Production of Estrone and Fractional Conversion of Circulating Androstenedione to Estrone in Women with Endometrial Carcinoma

Abstract

Postmenopausal women convert circulatory C₁₉ steroids to estrogen. In order to study the possible role of such estrogen in endometrial cancer, the determination of the fractional conversion of circulation Δ⁴-androstene-3,17-dione to estrone was attempted. However, in the course of this work it became apparent that the mathematical model upon which this determination is based does not adequately represent the true physiological conditions. The reasons for the inadequacy of the model are not apparent, although they seem to bear some relationship to obesity. The direction and magnitude of the deviation of the values determined from the true values are unknown. The values for the apparent fractional conversion of androstenedione to estrone in 9 postmenopausal women with endometrial cancer are strongly correlated with various indices of obesity. These values also correlate well with values for the apparent rate of production of estrone in our 9 patients and also in 5 postmenopausal patients with uteri bleeding reported in the literature, but no such correlation is evident for postmenopausal women without endometrial abnormality reported in the literature. The range of values for both the apparent fractional conversion and the apparent rate of production of estrone are similar to those reported by other workers using the same model. However, the data suggest that women with endometrial cancer may produce estriol by a pathway not involving circulating estrone.