Steroid Hormone (AWKD)

Question 0

Where does steroid hormone synthesis take place?

Answer 0

Cholesterol to pregnenolone in inner mitochondrial membrane. Pregnenolone to 11- deoxycortisol in ER. rest in mitochondrial membrane.

Question 1

What is the rate limiting step of steroid hormone synthesis?

Answer 1

Cholesterol ➡️ pregnenolone
Enzyme: desmolase complex (aka cholesterol side chain cleavage enzyme CYAP 11A1, P450 scc
Requires: O2 and NADPH

Question 2

How is cholesterol transported into the mitochondria?

Answer 2

StAR steriodogenic acute regulatory protein

Question 3

What hormone is released in the z. Glomerulusa?

Answer 3

Aldosterone

Question 4

What hormone is released by the z. Fasciulata?

Answer 4

Cortisol

Question 5

What is released by the z. Reticulatis (and the z. Fasciulata)?

Answer 5

Androgens (DHEA, androstenedione)

Question 6

What stimulates cortisol?

Answer 6

ACTH

Question 7

What stimulates aldosterone?

Answer 7

Angiotensin I/II

Question 8

What stimulates estradiol?

Answer 8

FSH

Question 9

What stimulates progesterone and testosterone?

Answer 9

LH

Question 10

What is the effect of cortisol?

Answer 10

Increased gluconeogenesis
Anti-inflammatory (inhibits phospholipase a2)
Protein breakdown in muscle (counteracts affects of insulin)

Question 11

How is cortisol transported in blood?

Answer 11

75% bound to transporting

15% bound to albumin

Question 12

What is the affect of aldosterone?

Answer 12

Raises blood pressure
Increased fluid volume
Increases sodium uptake

Question 13

What is the function of estrogens?

Answer 13

Control menstrual cycle.

Female secondary sex characteristics

Question 14

What is the function of progesterone?

Answer 14

Secretory phase of uterus and mammary glands

Implantation and maturation of fertilized ovum

Question 15

Where are the androgens produced by the z. Reticularis and z. Fasciculata converted to estradiol or testosterone?

Answer 15

Estradiol: fat cells
Testosterone: peripheral tissue (testes)

Question 16

How does LH affect testosterone synthesis? Where does this occur?

Answer 16

Increases cAMP and PKA in Leydig cells

Question 17

Where is DHT made and why is it significant?

Answer 17

More potent form of testosterone made in Sertoli cells

Question 18

What is the effect of testosterone?

Answer 18

Stimulates spermatogenesis
Male secondary sex characteristics
Promotes anabolism
Masculinization of fetus

Question 19

What is the general mechanism of steroid signal transduction?

Answer 19

Hormone protein complex travels to cell
Hormone released
Travels through membrane to the nucleus
Binds to receptor protein in nucleus
Receptor protein forms hormone response element (HRE) complex
This causes the transcription of various genes to increase or decrease

Question 20

What is the effect of 3-beta-hydroxysteroid dehydrogenase deficiency?

Answer 20

No glucocorticoids (cortisol), mineralcorticoids (aldosterone), androgens or estrogens. Salt excretion in urine (absence of aldosterone). Female-like genitalia (absence of testosterone)

Question 21

What is the affect of 17-alpha-hydroxylase deficiency?

Answer 21

Glucocorticoids, androgens and estrogens still inhibited. Mineralcorticoids (aldosterone) can still be made, resulting in increased salt and fluid retention (hypertension).

Question 22

What is the affect of 21-alpha-hydroxylase deficiency?

Answer 22

Most common! Products are Absent(classic) deficient (non-classic)
Both cortisol and aldosterone are inhibited, lots of androgens are produced.
Masculinization of external genetalia in females, early virilization in males.

Question 23

What is the effect of 11-beta-hydroxylase deficiency?

Answer 23

Decrease in cortisol, aldosterone, and corticosterone
Increased deoxycorticosterone leads to fluid retention, suppression of RAAS. Causes hypertension.
Masculinization/virilization

Question 24

What is the biochemical basis of Cushing’s syndrome?

Answer 24

Hyperfunction of adrenal cortex. Leads to high cortisol. Protein loss and characteristic fat distribution.

Question 25

What is the biochemical basis of Addison’s disease?

Answer 25

Adrenal cortex atrophy (usually autoimmune)

Low aldosterone and cortisol.