Physiology II

Question 1

What reaction does Desmolase catalyze?

Answer 1

Cholesterol –> Pregnenolone (p.291)

Question 2

What drug inhibits desmolase?

Answer 2

Ketoconazole (p.291)

Question 3

What stimulates Desmolase activity?

Answer 3

ACTH (p.291)

Question 4

What two reactions are catalyzed by 21-hydroxylase?

Answer 4

Progesterone –> 11-deoxycorticosterone; 17-hydroxyprogesterone –> 11-deoxycortisol (p.291)

Question 5

What two reactions are catalyzed by 11b-hydroxylase?

Answer 5

11-deoxycorticosterone –> corticosterone; 11-deoxycortisol –> cortisol (p.291)

Question 6

What reaction is catalyzed by Aldosterone synthase?

Answer 6

Corticosterone –> aldosterone (p.291)

Question 7

What stimulates Aldosterone synthase?

Answer 7

Angiotensin II (p.291)

Question 8

What two reactions are catalyzed by 17a-hydroxylase?

Answer 8

Pregnenolone –> 17 hydroxypregnenolone; progesterone –> 17-hydroxyprogesterone (p.291)

Question 9

What two reactions are catalyzed by 3b-hydroxysteroid dehydrogenase?

Answer 9

17-hydroxypregnenolone –> 17-hydroxyprogesterone; Dehydropiandrosterone (DHEA) –> Androstenedione (p.291)

Question 10

What two reactions are catalyzed by aromatase?

Answer 10

Androstenedione –> estrone; testosterone –> aromatase (p.291)

Question 11

What reaction is catalyzed by 5a-reductase?

Answer 11

Testosterone –> DHT (p.291)

Question 12

Where are estrogens produced?

Answer 12

In the periphery and ovaries (p.291)

Question 13

What is the effect on mineralocorticoid, cortisol, and sex-hormone synthesis in a 17a-hydroxylase deficiency?

Answer 13

Increased mineralocorticoids, decreased cortisol, decreased sex hormones (p.291)

Question 14

What is the effect on mineralocorticoid, cortisol, and sex-hormone synthesis in a 21-hydroxylase deficiency?

Answer 14

Decreased mineralocorticoids, decreased cortisol, increased sex hormones (p.291)

Question 15

What is the effect on mineralocorticoid, cortisol, and sex-hormone synthesis in an 11b-hydroxylase deficiency?

Answer 15

Mineralocorticoids- increased 11-deoxycorticosterone, decreased aldosterone, decreased cortisol, increased sex hormones (p.291)

Question 16

What is characteristic of all adrenal enzyme deficiencies?

Answer 16

An enlargement of both adrenal glands due to increased ACTH stimulation because of decreased cortisol (p.291)

Question 17

What is the presentation of a 17a-hydroxylase deficiency in males?

Answer 17

Hypertension, hypokalemia; decreased DHT (pseudohermaphroditism); variable ambiguous genitalia, undescended testes (p.291)

Question 18

What is the presentation of a 17a-hydroxylase deficiency in females?

Answer 18

Hypertention, hypokalemia; externally phenotypic female with normal internal sex organs. Lack of secondary sex characteristics (p.291)

Question 19

What is the presentation of a 21-hydroxylase deficiency in males?

Answer 19

Hypotension, hyperkalemia, increased renin activity, volume depletion (p.291)

Question 20

What is the presentation of a 21-hydroxylase deficiency in females?

Answer 20

Hypotension, hyperkalemia, increased renin activity, volume depletion; masculinization leading to pseudohermaphroditism (p.291)

Question 21

What is the presentation of an 11b-hydroxylase deficiency in males?

Answer 21

Hypertension (11-deoxycorticosterone is a mineralocorticoid and is secreted in excess), masculinization (p.291)

Question 22

What is the presentation of an 11b-hydroxylase deficiency in females?

Answer 22

Hypertension (11-deoxycorticosterone is a mineralocorticoid and is secreted in excess), masculinization (p.291)

Question 23

What is the most common adrenal enzyme deficiency?

Answer 23

A 21-hydroxylase deficiency (p.291)

Question 24

What protein binds cortisol?

Answer 24

Corticosteroid-binding globulin (CBG) (p.292)

Question 25

What are the six main functions of cortisol?

Answer 25

1.) Maintains blood pressure; 2.) decreases bone formation; 3.) serves an anti-inflammatory/ immunosuppressant role; 4.) increases insulin resistance (diabetogenic); 5.) increases gluconeogenesis, lipolysis, proteolysis; 6.) inhibits fibroblasts (p.292)