Adrenal Physiology

Question 1

What is the rate limiting step of adrenal steroid synthesis?

Answer 1

Pregnenolone Synthesis. Enzyme Cyp11A1, regulated by ACTH release. Happens in mitochondria.

Question 2

What are the lab values of Congenial 21-hydroxylase deficiency?

Answer 2

Dec. cortisol, Dec. aldosterone, Inc. ACTH, Inc. Androgens. Patients will have hypotension.

Question 3

What are the lab values of Congenial 11-beta-hydroxylase deficiency?

Answer 3

Dec. cortisol, Dec. aldosterone, Dec. corticosterone, Inc. ACTH, Inc. Androgens, Inc. Deoxycortisone. Patients will have hypertension.

Question 4

What things produce Aldosterone?

Answer 4

Angiotensin II. ACTH only stimulates aldosterone production at high levels. Both ACTH and Angiotensin II increase bp. No feedback of aldosterone onto ACTH levels.

Question 5

What is Cushing DISEASE?

Answer 5

Excess ACTH secretion. Usually due to pituitary adenomas. ACTH is increased. Cortisol is increased.

Question 6

What lab values are associated with Iatrogenic (drug) or primary adrenal tumors causing cushing syndrome?

Answer 6

Inc. Cortisol. Dec. ACTH.

Question 7

What lab values are seen in Addison’s Disease?

Answer 7

Autoimmune disease. Congenital adrenal dysgenesis or hormone insufficiency seen. Dec. Cortisol. Dec. Aldosterone. Inc. ACTH. Inc. MSH (POMC).

Question 8

What things other than Addison’s Disease can cause primary adrenal insufficiency?

Answer 8

Sudden steroid (exogenous cortisol) drug withdrawal. Leads to decreased ACTH.