Steriodogenesis & Biosynthetic Proteins

Question 1

StAR

Answer 1

in ~all steriogenic cells that produce progestins -shuttles cholesterol into the mitochondria

Question 2

P450scc (CYP11A)

Answer 2

-in theca cells and GC -converts cholesterol into pregnenolone

Question 3

3Beta-HSD

Answer 3

-in theca cells and GC -converts pregnenolone into progesterone; -converts DHEA into androstenedione

Question 4

P450 17alpha/C17.20 lyase (CYP17)

Answer 4

-in theca cells -converts progesterone into androtenedione -converts pregnenolone into DHEA

Question 5

P450 aromatase (CYP19)

Answer 5

-in GC -converts androstenedione into estrone; -converts testosterone into E2

Question 6

17Beta-HSD

Answer 6

-GC and theca cells -converts estrone into E2 -converts androstenedione into testosterone

Question 7

CYP17

Answer 7

• catalyzes conversion of 17alpha hydroxyprogesterone (P5) to androtendione
• expressed in preovulatory theca cells and zona reticularis

Question 8

CYP21

Answer 8

• Catalyzes the conversion of 17alpha hydroxyprogesterone to 21 deoxycortisol
• expressed in zona reticularis

Question 9

CYP11A1

Answer 9

• RLS in de novo steriodogenesis
• expressed in preovulatory theca cells
• expressed in zona reticularis
• expressed/secreted by preovulatory granulosa cells

Question 10

CYP19

Answer 10

• expressed/secreted by preovulatory granulosa cells
• expressed in hypothalumus, mediates negative feedback

Question 11

17beta-HSD

Answer 11

• catalyzes conversion of estrone to estradiol
• catalyzes conversion of 17alpha

Question 12

17beta-HSD 3, 5

Answer 12

converts androstenedione to testosterone (testicular steriodogenesis)

Question 13

Androtensidione

Answer 13

• substrate for aromatase
• product of #beta-HSD2 activity
• bioactively weak ovarian steriod
• binds to androgen receptor

Question 14

Estrone

Answer 14

• espressed/secreted by preovulatory granulosa cells
• bioactively weak ovarian steriod

Question 15

Testosterone

Answer 15

• substrate for aromatase
• secreted by Leydig cells
• binds to androgen receptor

Question 16

Corticosterone

Answer 16

• weak glucocorticoid

Question 17

Estradiol-17Beta

Answer 17

• expressed/secreted by preovulatory GC
• secreted by Leydig cells
• major product of placental steroidogenesis

Question 18

Cortisone

Answer 18

• product of 11Beta-HSD2 activity
• weak gluticorticoid

Question 19

Estriol

Answer 19

• major product of placental steriodogenesis
• most abundant placental estrogen

Question 20

Dihydrotestosterone (DHT)

Answer 20

• reduction product of testosterone
• binds to androgen receptor

Question 21

Dehydroepinandrosterone sulfate

Answer 21

• predominant adrenal androgen

Question 22

17alpha-hydroxyprogesterone

Answer 22

immediate precursor for androtensidione

Question 23

Pregnenalone

Answer 23

• product of CYP11A activity
• bioactively weak ovarian steriod
• substrate for production of progesterone

Question 24

Progesterone

Answer 24

• expressed/secreted by preovulatory GC
• product of 3Beta-HSD activity
• major product of placental steroidogenesis

Question 25

aldosterone

Answer 25

• product of corticosterone metabolism

Question 26

estrogen receptor

Answer 26

• expressed/secreted by preovulatory GC
• expressed in hypothalamus, mediates negative feedback

Question 27

11beta-HSD2

Answer 27

catalyzes conversion of cortisol to cortisone