Lexicon
Estrone
Also known as E1
Definition
There are four principal endogenous estrogens: estrone (E1), estradiol (E2), estriol (E3), and estetrol (E4), the last of which is produced only in pregnancy. [1] Estrone, estradiol, and estriol undergo extensive metabolism primarily through phase I reactions such as hydroxylation, oxidation, and reduction, and through phase II conjugation reactions. [1] Estrogens including estrone are locally produced in adipose tissue throughout a woman's lifespan, a form of local (intracrine) sex-steroid biosynthesis. [2]
How it works
The pathways of androgen metabolism are not altered at menopause, but aromatization of DHEA, androstenedione, and testosterone to estrone and estradiol all increase with age, so androgen metabolism in general is affected more by age than by the menopause itself. [3] After menopause a decrease in circulating estrogen concentrations coincides with a relative increase in visceral adipose tissue, and local adipose sex-steroid biosynthesis may in turn help determine adipose tissue distribution. [2]
Connected concepts
How it's measured
Estrone (E1) is quantified in circulating blood as one of the endogenous estrogens; for example, in a meta-analysis of soy and male reproductive hormones estrone levels were measured in the serum or plasma of 239 men. [4] Aromatase inhibitors are assessed in part by how much they suppress estrone; for instance letrozole commonly suppresses circulating estrone and estradiol below the sensitivity limit of the assays used to measure them in postmenopausal women. [5]
What levels mean
Increased estrone concentration is one of the endogenous hormone exposures convincingly associated with a heightened breast-cancer risk, together with increased androstenedione, estradiol, and testosterone. [6] Alcohol intake is positively, though weakly, associated with higher concentrations of endogenous sex hormones including estrone, which may contribute to its effect on breast-cancer risk. [7] In men, neither soy protein nor isoflavone intake significantly affected estrone levels regardless of dose or study duration.
Community knowledge
## Mechanism
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- 1.Stanczyk FZ. Metabolism of endogenous and exogenous estrogens in women. J Steroid Biochem Mol Biol · 2024
- 2.Hetemäki N, Mikkola TS, Savolainen-Peltonen H. Female Adipose Tissue Sex Steroid Biosynthesis. Semin Reprod Med · 2025
- 3.Longcope C. Androgen metabolism and the menopause. Semin Reprod Endocrinol · 1998
- 4.Reed KE, Camargo J, Hamilton-Reeves J, Kurzer M, Messina M. Neither soy nor isoflavone intake affects male reproductive hormones: An expanded and updated meta-analysis of clinical studies. Reprod Toxicol · 2021
- 5.Haynes BP, Dowsett M, Miller WR, Dixon JM, Bhatnagar AS. The pharmacology of letrozole. J Steroid Biochem Mol Biol · 2003
- 6.Yiallourou A, Pantavou K, Markozannes G, Pilavas A, Georgiou A, Hadjikou A, Economou M, Christodoulou N.
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