Estrone – 004564

Estrone (E1) is a steroid, a weak estrogen, and a minor female sex hormone.^3,4 Estrone is one of three major endogenous estrogens, the others being estradiol and estriol.^3,4 Like the other estrogens, estrone is synthesized from cholesterol and secreted mainly from the gonads, though they can also be formed from adrenal androgens in adipose tissue. Estrone is primarily derived from metabolism of androstenedione in peripheral tissues, especially adipose tissues. Individuals with obesity have increased conversion of androstenedione to estrone, leading to higher concentrations. Estrone can be converted into estradiol and serves mainly as a precursor or metabolic intermediate of estradiol. In addition, an increase in the ratio of estrone to estradiol may be useful in assessing menopause in women.