Steroid Metabolism

Question 1

What are the 5 classes of steroids?

Answer 1

glucocorticoids
mineralcorticoids
androgens
estrogens
progestins

Question 2

where does synthesis and secretion of steroids occur?

Answer 2

adrenal cortex (cortisol, aldosterone)
ovaries and ovarian corpus luteum (estrogen and progestins)
testes (testosterone)

Question 3

What are steroid hormones and what do they use in the blood?

Answer 3

hydrophobic

carrier proteins

Question 4

what are the carrier proteins?

Answer 4

transcortin for cortisol
sex-hormone binding protein - sex hormones
can be carried non-sepcifically by albumin

Question 5

how is cholesterol that is used for steroid hormone synthesis take up?

Answer 5

LDL or HDL or its synthesized

Question 6

How is cholesterol stored?

Answer 6

cholesterol ester (CE)

Question 7

what is an important regulatory step of cortisol synthesis?

Answer 7

transport of cholesterol into the mitochondria

Question 8

What transport of cholesterol into the mitochondria ?

Answer 8

StAR (steroidogenic acute regulatory protein)

Question 9

what activates cholesterol esterase?

Answer 9

PKA

Question 10

what is the rate limiting enzyme of steroid hormone synthesis?

Answer 10

desmolase

Question 11

what does desmolase require?

Answer 11

NADPH and O2

Question 12

what oxidizes and isomerizes pregnenolone to progesterone?

Answer 12

3-beta-hydroxysterioud DH

Question 13

what are the names for desmolase?

Answer 13

cholesterol side chain cleavage enzyme
CYP 11A1
P450 scc

Question 14

What are most enzymes (hydroxylases) ins teroid synthesis dependent on?

Answer 14

cytochrom P450 enzymes

Question 15

what does z. glomerulosa release?

Answer 15

aldosterone

Question 16

what does z. fasciculata release?

Answer 16

cortisol

Question 17

what does z. fasciculata and z. reticular is release?

Answer 17

androgens, DHEA, androstenedione

Question 18

what stimulates the production of cortisol?

Answer 18

ACTH

Question 19

what stimulates the production of aldosterone?

Answer 19

angiotensin II/III

Question 20

what stimulates the production of estadiol?

Answer 20

FSH

Question 21

what stimulates the production of progesterone and testosterone?

Answer 21

LH

Question 22

how is cortisol synthesized?

Answer 22

from progesterone in the z. fasciculata of adrenal cortex

Question 23

what is cortisol needed for ?

Answer 23

gluconeogenesis

Question 24

what does cortisol lead to?

Answer 24

general degradation of muscle protein - counteracts the action of INSULIN

Question 25

what does cortisol inhibit?

Answer 25

receptor activated phospholipase A2 | induction of COX-2

Question 26

how is cortisol transported in blood (%)?

Answer 26

75% to transcortin | 15% to albumin

Question 27

what makes aldosterone?

Answer 27

produced from progesterone in the z. glomerulosa

Question 28

what are the main androgens?

Answer 28

DHEA and androstenedione

Question 29

what are weak androgens changed in fat cells to?

Answer 29

estradiol in peripheral tissue to testosterone

Question 30

what activates testosterone synthesis?

Answer 30

LH receptors in leydig cells increase c-AMP and PKA

Question 31

what do sertoli cells produce?

Answer 31

Di hydrotestosterone (DHT) - more potent that testosterone

Question 32

what is cushing syndrome due to?

Answer 32

hyperfunction of the adrenal cortex to due adrenocorticol tumor

Question 33

what levels of cortisol and ACTH are found in cushing syndrome?

Answer 33

high cortisol low ACTH in plasma *high cortisol in urine

Question 34

what does glucocorticoid excess lead to in cushing syndrome?

Answer 34

protein loss and to characteristic fat distribution

Question 35

what happens to the adrenal cortex in Addisons disease?

Answer 35

atrophy | by autoimmune destruction

Question 35

what happens to the adrenal cortex in Addisons disease?

Answer 35

atrophy | by autoimmune destruction

Question 36

what are the levels of aldosterone, cortisol and ACTH in addison's disease?

Answer 36

``` aldosterone = low cortisol = low ACTH = high ```

Question 36

what are the levels of aldosterone, cortisol and ACTH in addison's disease?

Answer 36

``` aldosterone = low cortisol = low ACTH = high ```