Estrone Sulfate: Production Rate and Metabolism in Man

Abstract

Since estrone sulfate (E₁S) is present at high concentration in plasma, we have examined the parameters of the plasma estrone, estradiol, E₁S system. The metabolic clearance rate of E₁S was 157 liter/day (range 70-292) in men and women. Estimated plasma production rates of E₁S were (μgrams per day): men, 77; women, early follicular phase, 95; women, early luteal phase, 182. The conversion of plasma estrone and estradiol to E₁S was measured and from these data and the metabolic clearance rates of the estrogens, the transfer factors were ρ^E₁^E₁^S = 0.54 and ρ^E₂^E₁^S = 0.65. Using average production rates, all plasma E₁S could be shown to be derived from plasma estrone and estradiol. The conversion of plasma E₁S to plasma estrone and estradiol was studied. The calculated transfer factors were: ρ^E₁^SE₁ = 0.21, ρ^E₁^SE₂ = 0.014. Essentially, similar data were obtained when E₁S was given by mouth to two subjects. We conclude: (a) E₁S is a major circulating plasma estrogen and has a long plasma half-life; (b) the large contributions of estrone and estradiol to plasma E₁S are more than sufficient to account for all the circulating plasma E₁S.