The Role of Estrogen in the Regulation of Erythropoietin Production1

Low doses of estradiol benzoate (2.5-10.0 μg/day X 5) inhibited the production of erythropoietin (Ep) in female rats exposed to various intensities of hypoxia. This was not attributable to the presence of either residual estradiol, or an inhibitor of Ep in plasma samples, since these plasmas had no inhibitory effect on Ep simultaneously injected into assay mice. Although normal females produced less Ep in response to hypoxia than normal males, ovariectomized rats showed a response equal to males. Estradiol treatment of ovariectomized animals lowered their Ep response to hypoxia down to the level of intact females. Only the largest dose employed (10.0 μ/day) had some inhibitory effect on Ep production in hypoxic males. (Endocrinology92: 358, 1973)