Steriodogenesis & Biosynthetic Proteins Flashcards
StAR
in ~all steriogenic cells that produce progestins -shuttles cholesterol into the mitochondria
P450scc (CYP11A)
-in theca cells and GC -converts cholesterol into pregnenolone
3Beta-HSD
-in theca cells and GC -converts pregnenolone into progesterone; -converts DHEA into androstenedione
P450 17alpha/C17.20 lyase (CYP17)
-in theca cells -converts progesterone into androtenedione -converts pregnenolone into DHEA
P450 aromatase (CYP19)
-in GC -converts androstenedione into estrone; -converts testosterone into E2
17Beta-HSD
-GC and theca cells -converts estrone into E2 -converts androstenedione into testosterone
CYP17
- catalyzes conversion of 17alpha hydroxyprogesterone (P5) to androtendione
- expressed in preovulatory theca cells and zona reticularis
CYP21
- Catalyzes the conversion of 17alpha hydroxyprogesterone to 21 deoxycortisol
- expressed in zona reticularis
CYP11A1
- RLS in de novo steriodogenesis
- expressed in preovulatory theca cells
- expressed in zona reticularis
- expressed/secreted by preovulatory granulosa cells
CYP19
- expressed/secreted by preovulatory granulosa cells
- expressed in hypothalumus, mediates negative feedback
17beta-HSD
- catalyzes conversion of estrone to estradiol
- catalyzes conversion of 17alpha
17beta-HSD 3, 5
converts androstenedione to testosterone (testicular steriodogenesis)
Androtensidione
- substrate for aromatase
- product of #beta-HSD2 activity
- bioactively weak ovarian steriod
- binds to androgen receptor
Estrone
- espressed/secreted by preovulatory granulosa cells
- bioactively weak ovarian steriod
Testosterone
- substrate for aromatase
- secreted by Leydig cells
- binds to androgen receptor
Corticosterone
- weak glucocorticoid
Estradiol-17Beta
- expressed/secreted by preovulatory GC
- secreted by Leydig cells
- major product of placental steroidogenesis
Cortisone
- product of 11Beta-HSD2 activity
- weak gluticorticoid
Estriol
- major product of placental steriodogenesis
- most abundant placental estrogen
Dihydrotestosterone (DHT)
- reduction product of testosterone
- binds to androgen receptor
Dehydroepinandrosterone sulfate
- predominant adrenal androgen
17alpha-hydroxyprogesterone
immediate precursor for androtensidione
Pregnenalone
- product of CYP11A activity
- bioactively weak ovarian steriod
- substrate for production of progesterone
Progesterone
- expressed/secreted by preovulatory GC
- product of 3Beta-HSD activity
- major product of placental steroidogenesis
aldosterone
- product of corticosterone metabolism
estrogen receptor
- expressed/secreted by preovulatory GC
- expressed in hypothalamus, mediates negative feedback
11beta-HSD2
catalyzes conversion of cortisol to cortisone
