Physiology II Flashcards
What reaction does Desmolase catalyze?
Cholesterol –> Pregnenolone (p.291)
What drug inhibits desmolase?
Ketoconazole (p.291)
What stimulates Desmolase activity?
ACTH (p.291)
What two reactions are catalyzed by 21-hydroxylase?
Progesterone –> 11-deoxycorticosterone; 17-hydroxyprogesterone –> 11-deoxycortisol (p.291)
What two reactions are catalyzed by 11b-hydroxylase?
11-deoxycorticosterone –> corticosterone; 11-deoxycortisol –> cortisol (p.291)
What reaction is catalyzed by Aldosterone synthase?
Corticosterone –> aldosterone (p.291)
What stimulates Aldosterone synthase?
Angiotensin II (p.291)
What two reactions are catalyzed by 17a-hydroxylase?
Pregnenolone –> 17 hydroxypregnenolone; progesterone –> 17-hydroxyprogesterone (p.291)
What two reactions are catalyzed by 3b-hydroxysteroid dehydrogenase?
17-hydroxypregnenolone –> 17-hydroxyprogesterone; Dehydropiandrosterone (DHEA) –> Androstenedione (p.291)
What two reactions are catalyzed by aromatase?
Androstenedione –> estrone; testosterone –> aromatase (p.291)
What reaction is catalyzed by 5a-reductase?
Testosterone –> DHT (p.291)
Where are estrogens produced?
In the periphery and ovaries (p.291)
What is the effect on mineralocorticoid, cortisol, and sex-hormone synthesis in a 17a-hydroxylase deficiency?
Increased mineralocorticoids, decreased cortisol, decreased sex hormones (p.291)
What is the effect on mineralocorticoid, cortisol, and sex-hormone synthesis in a 21-hydroxylase deficiency?
Decreased mineralocorticoids, decreased cortisol, increased sex hormones (p.291)
What is the effect on mineralocorticoid, cortisol, and sex-hormone synthesis in an 11b-hydroxylase deficiency?
Mineralocorticoids- increased 11-deoxycorticosterone, decreased aldosterone, decreased cortisol, increased sex hormones (p.291)
What is characteristic of all adrenal enzyme deficiencies?
An enlargement of both adrenal glands due to increased ACTH stimulation because of decreased cortisol (p.291)
What is the presentation of a 17a-hydroxylase deficiency in males?
Hypertension, hypokalemia; decreased DHT (pseudohermaphroditism); variable ambiguous genitalia, undescended testes (p.291)
What is the presentation of a 17a-hydroxylase deficiency in females?
Hypertention, hypokalemia; externally phenotypic female with normal internal sex organs. Lack of secondary sex characteristics (p.291)
What is the presentation of a 21-hydroxylase deficiency in males?
Hypotension, hyperkalemia, increased renin activity, volume depletion (p.291)
What is the presentation of a 21-hydroxylase deficiency in females?
Hypotension, hyperkalemia, increased renin activity, volume depletion; masculinization leading to pseudohermaphroditism (p.291)
What is the presentation of an 11b-hydroxylase deficiency in males?
Hypertension (11-deoxycorticosterone is a mineralocorticoid and is secreted in excess), masculinization (p.291)
What is the presentation of an 11b-hydroxylase deficiency in females?
Hypertension (11-deoxycorticosterone is a mineralocorticoid and is secreted in excess), masculinization (p.291)
What is the most common adrenal enzyme deficiency?
A 21-hydroxylase deficiency (p.291)
What protein binds cortisol?
Corticosteroid-binding globulin (CBG) (p.292)
What are the six main functions of cortisol?
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)
