Steroid Hormones

Question 1

What are the 5 classes of steroid hormones?

Answer 1

Glucocorticoids
Mineralocorticoids
Progesterone
Androgens
Estrogen

Question 2

Which classes make up the corticosteroids?

Answer 2

1) Glucocorticoids
2) Mineralocorticoids

Question 3

Which classes make up the sex steroids?

Answer 3

1) Progesterone
2) Androgens
3) Estrogen

Question 4

What is Addison’s Disease

Answer 4

Failure to make Aldosterone/Cortisol

Low levels of corticosteroids

Question 5

What is Cushing Syndrome

Answer 5

Excess overproduction of cortisol by the adrenal glands

Question 6

Glucocorticoid function and example

Answer 6

Cortisol
- guide conversion of sugar, fat, protein to usable energy
- inhibit swelling and inflammation
- suppress immune responses

Question 7

Mineralocorticoids function and example

Answer 7

Aldosterone
- regulate inorganic molecules to maintain H2O
- retention of Na+, excretion of K+ and H+
- retention of H2O leads to an increase in BV and BP
- release regulated by sensors in kidney

Question 8

Androgens function and example

Answer 8

Testosterone
- development of sex organs
- converted to DHT in target tissues
- increases 30x in puberty

Question 9

Progesterone

Answer 9

• prepares endometrium for implantation
• inhibits development of a new follicle
• mammary gland development

Question 10

StAR Complex

Answer 10

Steroidogenic Acute Regulatory Protein
- Moves cholesterol into the mitochondria for synthesis
- Fatal if non-functional

Question 11

When does cortisol synthesis occur

Answer 11

Occurs in the adrenal cortex following ACTH release by the pituitary gland

Question 12

Which steps of cortisol synthesis occur in the mitochondria?

Answer 12

Cholesterol > Pregnenolone ….> Cortisol

Question 13

Cortisol synthesis intermediates

Answer 13

Cholesterol > Pregnenolone > Progesterone > 17-⍺-Hydroxyprogesterone > 11-Deoxycortisol > Cortisol

Question 14

Cortisol synthesis intermediates

Answer 14

20⍺-22 Desmolase
3ß-hydroxysteroid DH
17⍺-Hydroxylase
21⍺-Hydroxylase
11ß-Hydroxylase

Question 15

Which step converts NADPH and O2 to NADP

Answer 15

11ß-Hydroxylase converting 11-Deoxycortisol to Cortisol

Question 16

Where does Aldosterone synthesis occur?

Answer 16

Adrenal Cortex

Question 17

Aldosterone synthesis intermediates

Answer 17

Cholesterol
Pregnenolone
Progesterone
11-deoxycortisone
Corticosterone
Aldosterone

Question 18

Aldosterone synthesis enzymes

Answer 18

20⍺-22 Desmolase
3ß-hydroxysteroid DH
21⍺-Hydroxylase
11ß-Hydroxylase
Aldosterone Synthase

Question 19

When is the ∆5 pathway of testosterone synthesis present as opposed to ∆4?

Answer 19

∆5 is dominant in humans, but ∆4 is still active (hamsters)

Question 20

Testosterone ∆5 pathway intermediates

Answer 20

Cholesterol
Pregnenolone
17⍺-Hydroxypregnenolone
DHEA
Androstenedione
Testosterone
Estradiol (Estrone)

Question 21

Testosterone ∆4 pathway intermediates

Answer 21

Cholesterol
Pregnenolone
Progesterone
17⍺-Hydroxyprogesterone
Androstenedione
Testosterone
Estradiol (Estrone)

Question 22

Testosterone ∆5 pathway enzymes

Answer 22

20⍺-22 Amylase
17⍺-hydroxylase
17⍺-hydroxylase
3ß-hydroxysteroid DH
17ß-hydroxysteroid DH
Aromatase

Question 23

Testosterone ∆4 pathway Enzymes

Answer 23

20⍺-22 Amylase
3ß-hydroxysteroid DH
17⍺-hydroxylase
17⍺-hydroxylase
17ß-hydroxysteroid DH
Aromatase

Question 24

Finasteride mechanism of action

Answer 24

Inhibition of 5⍺-reductase which prevents the conversion of testosterone to the more active DHT

Question 25

What is Congenital Adrenal Hyperplasia

Answer 25

Mutations in adrenal glands that prevents the synthesis of hormones and development of gonads

Question 26

CAH mutations

Answer 26

3ß-hydroxysteroid DH 17⍺-hydroxylase 21⍺-hydroxylase 11ß-hydroxylase

Question 27

Estrogen effect on disease

Answer 27

- increased exposure linked to some cancers - low levels lead to osteoporosis

Question 28

Testosterone effect on disease

Answer 28

- increased exposure linked to CV disease and CaP - low levels: ED, more fat, insulin insensitivity, elevated TG, low HDL

Question 29

Can steroid hormones pass through membranes?

Answer 29

Yes, they are lipid soluble

Question 30

Corticosteroid Binding Globulin

Answer 30

Complexes with Cortisol to carry it through the blood

Question 31

Sex Steroid Binding Globulin

Answer 31

Complexes with Testosterone and Estradiol to bring it through the blood

Question 32

Estrogen Receptor mechanism

Answer 32

Estrogen enters cytosol and binds to ER, displacing a HSP ER then travels to nucleus and binds to ERE and other co-activators to enhance transcription

Question 33

Tamoxifen mechanism of action

Answer 33

Prevents ER from binding to coactivators by preventing conformational change This then prevents transcription ie cancer (only helps if the cancer is hormone-responsive) - can also increase risk of uterine cancer bc coactivators can still bind even w/o conformational change