Hormondruse - Prufung3

Question 1

Where are glucocorticoids produced, and what is their fxn?

Answer 1

Adrenal cortex, regulate glucose metabolism

Question 2

What is the endogenous adrenal corticoid?

Answer 2

cortisol

Question 3

Where is cortisol produced?

Answer 3

Adrenal cortex - fasciculate and reticularis

Question 4

How does cortisol’s production compare to aldosterone?

Answer 4

Produced 100x the level of aldosterone

Question 5

The plasma concentration of this is 0.4 micromolar, and 96% of it is bound to corticosteroid binding globulin.

Answer 5

corticosol

Question 6

Adrenal cortical hormones are derived from what?

Answer 6

cholesterol

Question 7

This is the enzyme that converts 17-hydroxyprogesterone into 11-deoxycortisol.
Hint: 21-B-________-ase

Answer 7

21-B-hydroxylase.

It is a cytochrome P450 enzyme (p450C21)

Question 8

Stressors signal production of _____ (what is the releasing hormone) –> this then triggers ACTH release –> ACTH triggers this gland _____ to secrete cortisol –> cortisol results in ____ (- or +) feedback at level of hypothalamus and pituitary.

Answer 8

CRH –> ACTH –> adrenal gland –> cortisol –> negative feedback

Question 9

This is a disease caused by deficiency in biosynthetic enzymes (most commonly 21-B-hydroxylase). Results in masculinization, sexual precocity, accelerated linear growth. This is b/c biosynthesis diverts to DHEA and androstenedione.

No cortisol: can’t hvae negative feedback to hypothalamus’s CRH or pituitary ACTH –> so adrenal steroid biosynthesis increases –> adrenal hypertorphy

Answer 9

CAH: Congenital Adrenal Hyperplasa

Question 10

What ist he treatment for CAH?

Answer 10

Glucocorticoid mineralocorticoid replacement

-earlier=better, for 2ndary sex characteristics

Question 11

What is the receptor for ACTH called, and what type of receptor is it?

Answer 11

Name: MC2R (Melanocortin Type 2 Receptor)
Type: Gs-type G protein signaling receptor
- Signals via adenylyl cyclase (AC) to produce cAMP –> cAMP releases IP3 from ER and DAG from membrane –> activates PKC.

Question 12

How does ACTH work? (What does it do)?

Answer 12

• Increases steroid synthesis

- Trophic effect on adrenal gland.

Question 13

What type of receptor does cortisol hhave?

Answer 13

intracellular glucocorticoid receptor (GR) binds cortisol in cytoplasm –> translocates to nucleus –> activates transcription

Question 14

This hormone stimulates FSH.

• Protein hormone
• Homodimer w/2 inhibin-B chains
• Stimulates release of FSH, but not LH

Answer 14

Activin

Question 15

This hormone suppresses secretion of FSH, but not LH.

• Made by granulosa cells
• found in follicular fluid
• protein hormone

Answer 15

Inhibin (folliculostatin)

Question 16

This hormone is secreted by the developing follicle. It’s a protein hormone. Suppresses FSH.

• Single chain glycosylated polypeptide
• Decreases levels of FSH mRNA, inhibits FSH secretion in vitro

Answer 16

Follistatin

Question 17

Androgen synthesis occurs in these cells of the testis.

Answer 17

Leydig cells

Question 18

Spermatogenesis occurs here in the testis

Answer 18

seminiferous tubules

Question 19

Concentration of testosterone in the testis is __x that of it in the peripheral circulation

Answer 19

100x

Question 20

44% of circulating testosterone is bound with high-affinity to:____

Answer 20

TEBG (testosterone-estradiol-binding-globulin)

Question 21

Synthesis of TEBG stimulated by this hormone:

Answer 21

estradiol

Question 22

_____ is the major androgen in tissues of the Wolffian duct, pituitary, and kidney.

Answer 22

testosterone

Question 23

At the urogenital sinus, testosterone is converted into dihydrotestsosterone (DHT), using this enzyme:

Answer 23

5a-reductase (resides on nuclear membrane)

Question 24

In the brain, testosterone can be aromatized to: ____

Answer 24

estradiol

Question 25

Which (DHT or testosterone) is more potent in attaching to androgen response elements in nuclei?

Answer 25

DHT - 100x more potent.

Question 26

How does DHT formation amplify testosterone action?

Answer 26

1. Conversion of testosterone to DHT is irreversible (DHT, unlike testosterone, can’t be converted to estrogen)
2. DHT has a higher affinity for the androgen receptor.
3. DHT receptor complex transformed more efficiently to DNA binding state than is the testosterone receptor complex.

Question 27

The SRY produces ____ which promotes devt of testis

Answer 27

TDF

Question 28

TDF influences cells of the medulla of the primitive sex cords to proliferate into ____ cells, ____, and ____.

Answer 28

Sertoli cells
Seminiferous tubules
Rete testis tubules.

Question 29

Testis is differentiated and secretes tesosterone at about the 7th-8th wk of embryonic life. It comes (before or after) hormonal secretion of anterior pituitary.

Answer 29

before – so initially, it is independent of pituitary control.

Question 30

If the gonad develops into a testis, what happens to the Wolffian duct and Mullierian system? What happens to UG sinus?

Answer 30

Wolffian duct –> develops into epididymis, VD, seminal vesicles.

Mullerian –> in response to Mullerian Inhibitory Factor (MIF) made by Sertolli cells –> involutes

UG sinus –> in response to DHT –> differentiates into penis, scrotum, prostate, urethra.

Question 31

5-ARD deficiency is caused by a mutation of the gene that converts…

Answer 31

testosterone to DHT.
People w/this can have: normal male ext genitalia, ambiguous genitalia, or normal female genitalia. (born w/testis and Wolffian structures)

Question 32

Androgens _____ bone maturation –> results in ____ of epiphysial plates.

Answer 32

promote bone maturation –> resulting in CLOSURE of epiphyseal plates.
**But androgens stimulate linear bone growth.

Question 33

Negative feedback action of LH is due to: ___ and ____

Answer 33

testosterone and estradiol