The main oestrogen in humans, it is a steroid (or sex) hormone produced by aromatization of testosterone (i.e., the transformation of testosterone into estradiol). It acts on oestrogen receptors throughout the body, with the largest amounts of estradiol being produced by the granulosa cells of the ovaries. Essential for sexual functioning, it also supports bone growth in terms of strength and density. While labeled the ‘female hormone’, smaller amounts, however, are derived from testicular and adrenal testosterone. In men, aromatization has been implicated in the exacerbation of prostate hypertrophy and and increased risk of cancer due to elevated levels of estrogen.
See Adolescent growth spurt, Estrogen, Hormones, Menarche, Puberty, Steroid hormones, Testosterone