Estrogen and its synthesis

This document discusses estrogen, including its structure, types, and biosynthesis. There are three main naturally occurring forms of estrogen: estrone, estradiol, and estriol. Estrone was the first estrogen to be isolated from pregnant women's urine. Estradiol is the most biologically active form and the main estrogen produced in premenopausal women. Estrogen structures contain steroid nuclei and are synthesized from cholesterol through a series of hydroxylation and aromatization reactions in various tissues like the ovaries and liver.