Oestrogen

Oestrogen
Lipidomics Gateway (23 May 2012) [doi:10.1038/lipidmaps.2012.13]
Although the reproductive function of oestrogens is largely mediated by classical genomic signalling, this group ofsteroid hormones can also induce rapid signalling to affect other physiological functions.
Oestrogens comprise a small group of steroid hormones that are important for reproductive function — in mammalsfor the oestrus cycle, from which they take their name. The most biologically active oestrogen, oestradiol (abbreviated to E2 owing to the presence of two hydroxyl groups in its molecular structure;also known as 17β-oestradiol), can be synthesized directly from testosterone by an aromatase, or from androstenedione by aromatization to oestrone (E1) and subsequent conversion. Oestriol (E3) is anabundant but less potent oestrogen, whereas oestetrol (E4) is synthesized by the fetus during pregnancy.
E2 is synthesized in the ovaries of women of a fertile age, or in extragonadal sites — mainlyadipose tissue, brain, bone, vascular endothelial cells, bone cells, breast tissue and skin fibroblasts — in postmenopausal women and in men, who also produce E2 in the testes 1 . The production ofoestrogen, the levels of which fluctuate during the human menstrual cycle, peaking prior to ovulation, is stimulated by follicle-stimulating hormone (FSH). The production of FSH, however, is, in turn,inhibited by oestrogen, and this negative feedback forms the basis of many synthetic oestrogen-containing contraceptives, which are designed to prevent ovulation.
As steroid hormones, oestrogens candiffuse across the cell membrane to reach their cytoplasmic receptors, which are expressed in a wide range of cell types and vary in levels according to age, developmental status and health/diseasestatus 1 . Oestrogen receptor (ER) subtype α and ERβ predominantly mediate the reproductive effects of oestrogen as ligand-activated transcription factors that bind as homodimers to oestrogen-response...