What are the benefits of oestrogens in Males??

estradiol plays a beneficial role in the lipogenesis Both male and female aromatase-deficient (Cyp19KO) persons exhibit obesity and dyslipidemia , proving that estradiol plays a beneficial role in the lipogenesis. However, an adverse effect of adipose tissue-driven estradiol is also indicated in the pathogenesis of breast cancer. For instance, in a breast with a tumor, adipose tissues proximal to the tumor exhibit higher aromatase activity than those distal to the tumor 

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Estrogens are a class of steroid hormones that regulate the development and function of male and female reproductive organs. In the ovary, estrogen synthesis begins in theca cells with androgen synthesis and ends with conversion of androgens to estrogens in granulosa cells by the enzyme aromatase.

In the male gonad, estrogens are synthesized in the Leydig cells, Sertoli cells, and mature spermatocytes.

Like other steroid hormones, estrogens enter passively into the cells and bind to the estrogen receptors, which then regulate the transcription of downstream estrogen-responsive genes. Among the number of different forms of estrogens, 17β-estradiol (estradiol) is the most common and potent form of estrogen in mammals.

 Extragonadal organs sourcesa;-Estradiol is also produced in a number of extragonadal organs, including the adrenal glands, brain, adipose tissue, skin, pancreas , and other sites yet to be identified. The discoveries of extra-gonadal sites of estradiol synthesis greatly expands our knowledge of the novel roles of estrogens beyond the reproductive system.

EXTRA-GONADAL SITES OF ESTROGEN SYNTHESIS AND ITS LOCAL ROLES

The first discovery of extra-gonadal estrogen synthesis was made in 1974 by Hemsell and his colleagues when they made an unexpected observation that androgens were converted to estrogens in adipose tissue . Since then, a number of other extra-gonadal sites of estrogen synthesis have been discovered. Adipose tissues are considered to be the major source of circulating estrogen after the gonads in both men and women, and the contribution made by the adipose tissues to the total circulating estrogens increases with advancing age .

 The chemical structure and biological activity of the estrogens synthesized in the extra-gonadal sites are not different from those that are produced by the gonads. However, there are unique features that make the extra-gonadal estrogen synthesis differ from the gonadal synthesis. A major difference is in the biochemical pathway of estrogen synthesis. The tissues and cells of the extra-gonadal sites of estrogen synthesis are unable to synthesize C19 steroids, the precursors of estrogen synthesis, but are able to convert C19 steroids to estrogens, a critical and rate-limiting step mediated by Cyp19 aromatase.

Hence, extra-gonadal estrogen synthesis is dependent on an external source of C19 precursors and the level of aromatase expression. Because C19 steroids can be supplied to a local tissue via circulation and are converted to estrogens in any tissue where aromatase is expressed, the presence of aromatase expression in a local tissue confirms extra-gonadal estrogen synthesis. . lists the peripheral tissues that express aromatase and are therefore able to convert C19 precursors to estrogens.

These extra-gonadally synthesized estrogens are thought to act and be metabolized locally, which limits their systemic effects .. Another unique feature of extra-gonadal estrogen synthesis is that while the total amount of estrogen synthesized in each tissue may be small, the local tissue concentrations of estrogens could be high enough to exert biological impact locally. The functional roles of estrogens are mediated mostly by estrogen receptors that are nuclear receptor transcription factors. Therefore, a tissue that expresses one or more estrogen receptors is considered to be a target of estrogenic regulation lists key organs and tissues that express estrogen receptors.

Extra-gonadal sites of estrogen synthesis

Sites	Evidence of 17β-estradiol synthesis
	Cyp19 mRNA	Cyp19 protein	17β-estradiol
Brain	Astrocyte Hippocampus and hypothalamus	Astrocyte  , GnRH  , Dentate gyrus/ pyramidal cell Interneurons  , Granular cell Purkinje cell Ependymal andsubependymal cell  .	Astrocyte .
Fat	Stromal cell  , Adipocyte	Stromal cell  , Adipocyte, mesenchymal cell
Bone	Osteoblast	Osteoblast	Osteoblast
Liver	HepG2 hepatoma andhepatocellular carcinoma  , Hepatocyte	HepG2 hepatoma and hepatocellular carcinoma	HepG2 hepatoma and hepatocellular carcinoma
Adrenal gland	Adrenocortical cell	Adrenocortical cell	Adrenocortical cell
Intestine	Parietal cell	Parietal cell	Parietal cell
Skin	Fibroblast  . Keratinocyte  .	Fibroblast	Fibroblast
Blood vessel	Smooth muscle cell	Smooth muscle cell
Spleen	T cell	T cell