Estrogens are major sex hormones in females that play a very important role in both menstrual and estrous reproductive cycles. Natural estrogens are steroid hormones. In females the primary producers of estrogen are ovaries and through gestation it is produced by the placenta. The ovarian production of estrogens by the granulosa cells of the ovarian follicles and corpora lutea is stimulated by Follicle-stimulating hormone (FSH). The other tissues that produce estrogen in smaller quantities are the liver, adrenal glands, and the breasts. Due to vasculo-protective action of estrogen which helps in preventing atherosclerosis women suffer less from heart disease. The three major naturally occurring estrogens in women are estrone (E1), estradiol (E2), and estriol (E3). Estradiol is the predominant estrogen throughout generative years each in terms of absolute serum levels and also in terms of estrogenic activity. During menopause, the predominant circulating estrogen is estrone and during pregnancy the predominant circulating estrogen in terms of serum levels is estriol.
Estriol is the most abundant of all the three estrogens. Estriol is the weakest and estradiol is the strongest with an efficiency of approximately 80 times that of estriol. Hence, estradiol is the most significant estrogen in non-pregnant females who are between the menarche and menopause stages of life. However, during pregnancy this role is taken up by estriol and in postmenopausal women the primary form of estrogen in the body estrone. Another type of estrogen that is produced only during pregnancy called estetrol (E4). The precursors for the production of estrogens are androgens. Journal of Steroids & Hormonal Science is an official journal of OMICS group international that publishes all the papers related to estrogens. The papers published in the journal are subjected to strict and thorough peer review process.
Last date updated on July, 2014