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deh y droepiandrosteron e (DHEA)

Synthesis of sex steroids. NAD(P)H. NAD(P)+. 17OHSDH. deh y droepiandrosteron e (DHEA). androst e n e diol. 3OHSDH. 5 a redu ctase. androst e n e dion e. testosteron e. 5 a dih y drotestosteron e. aromat ase. es tron e (C18). es tradiol (C18). Aromat ase rea ction.

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deh y droepiandrosteron e (DHEA)

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  1. Synthesis of sex steroids NAD(P)H NAD(P)+ 17OHSDH dehydroepiandrosterone (DHEA) androstenediol 3OHSDH 5a reductase androstenedione testosterone 5a dihydrotestosterone aromatase estrone (C18) estradiol (C18)

  2. Aromatase reaction localization: sER testosterone estradiol (C18) C19 OHase X 2, H2O leaves spontaneously

  3. 17-hydroxysteroid dehydrogenase isoenzymes 17OHSDH-I NADPH+H+ reductase in cytosol placenta, ovaries, adipose tissue NADP+ estrone estradiol 17OHSDH-III NADPH+H+ reductase in ER testis androstenedione testosterone NADP+ 17OHSDH-II testosterone androstenedione oxidation=inactivation in ER liver, intestine, placenta NAD+ NADH+H+ estradiol estrone

  4. Testis, Leydig cell - P45017 (17-hydroxylase/17,20 lyase) - 17hydroxysteroid dehydrogenase : NAD(P)H, not a cytochrome P450! - NO P45021 LH, hCG receptor cholesterol ester cAMP  cholesterol ER surface P45017 cholesterol P450scc 17OHSDH 17 OH- pregnenolone DHEA pregnenolone pregnenolone androstenediol 3OHSDH 17 OH- progesterone progesterone androstenedione testosterone mitochondrium inner membrane

  5. 5a reductase androgen effects testosterone testis spermatogenesis psychosexual identity protein synthesis in the muscle male voice male-type hair growth 5a reductase NADPH + H+ in target cells, on ER surface T,DHT induce its synthesis NADP+ male external organs development and function of the prostate male-type hair growth male-type baldness dihydrotestosterone - more efficient (binds to A receptor with higher affinity, DHT-A receptor complex is a better inducer) - no way back to estrogens

  6. 5a reductase deficiency (pseudohermaphroditismus masculinus) XY, testis normal plasma T, but DHT , T/DHT ratio  female or mixed external sex organs  the newborn is considered as a girl pubertal virilization  diagnosis

  7. Ovarium – Two-cell theory theca interna interstitial cells - P45017 (17-hydroxylase/17,20 lyase) - NO P45021, 17hydroxysteroid dehydrogenase , aromatase P45017 cholesterol cholesterol P450scc 17 OH- pregnenolone DHEA pregnenolone pregnenolone 3OHSDH 17 OH- progesterone progesterone androstenedione progesterone diffusion progesterone androstenedione testosterone 3OHSDH aromatase pregnenolone pregnenolone P450scc estrone estradiol 17OHSDH cholesterol granulosa cell LDL-cholesterol, from plasma - 17hydroxysteroid dehydrogenase, aromatase - NO P45017 , P45021 dependent on the substrate in luteal phase, after vascularization

  8. Placenta like the granulosa cell P450scc 3OHSDH progesterone cholesterol pregnenolone sulfatase 17OHSDH DHEAS DHEA androstenediol maternal/fetal adrenal cortex z.reticularis androstenedione testosterone aromatase estrone estradiol

  9. Inactivation of maternal steroids in the placenta 17OHSDH-II oxidation=inactivation ER vascular endothelial cells testosterone androstenedione mother NAD+ NADH+H+ estradiol estrone 11OHSDH mother oxidation=inactivation cortisol cortisone NAD+ NADH+H+

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