The Adrenal Gland

Question 1

What is the diagnostic test for determining priimary and secondary hyper-aldosteronism? Also, what values indicate a primary and secondary hyper-aldosteronism?

Answer 1

1) PRA (Plasma Renin Activity) & PAC (Plasma Aldosterone Concentration) Ratio 2) Primary Hyperaldosteronism (PAC/PRA of > 20:1) Secondary Hyperaldosteronism (PAC/PRA of ~ 10)

Question 2

All congenital adrenal enzyme deficiences are characterized via what?

Answer 2

Adrenal Hyperplasia, due to positive feedback, increasing ATCH hormone levels

Question 3

What are the expected lab values and presentation for a 17-a-hydroxylase enzyme deficiency?

Answer 3

Labs: Decreased Androstenedione & Cortisol Presentation: Males: Undescended testis Females: Lack of 2ndry sexual development

Question 4

What are some lab findings and presentations for a 21-B-hydroxylase deficiency

Answer 4

Labs: Increased Renin Activity & Increased 17-hydroxy progesterone Presentation: Salt Wasting (in infancy) Precocoius puberty & Virilization

Question 5

What are some lab values and presentation that would be found with a 11B-hydroxylase deficiency?

Answer 5

Labs: Increased DOC & BP (but decreased Aldosterone), Decreased Cortisol, and Increased Sex Hormones. Also seen would be decreased Renin activity (d/t increased DOC activity). Presentation: Virilization

Question 6

What is the strongest form of exogenous cortisol?

Answer 6

Dexamethasone

Question 7

What does a high mexthasone test differentiate between?

Answer 7

A pituitary tumor and a non pituitary tumor

Question 8

What is Addison’s Disease?

Answer 8

• Autoimmune disease of the Adrenal Gland (Decreased Cortisol and Aldosterone production)
• Increased ACTH and CRH production

Question 9

What is the mechanism behind hyperpigmentation in those with Addison’s Disease

Answer 9

1) Addison’s DIsease: Unable to produce Cortisol or Aldosterone; High ACTH levels
2) ACTH levels are then broken down, via post-translation modification of POMC –> a-MSH–> drives Melanin synthesis
3) Melanin accounts for the hyperpigmentation ]

Question 10

What is Cosyntropin and what does it test for?

Answer 10

1) Cosyntropin (Synthetic ACTH)
2) Tests for Adrenal Insufficiency (1*, 2*, or 3*)

Question 11

What are four possible causes of Primary Adrenal Insufficiency (Addison’s Disease)?

Answer 11

1) Autoimmune Disease
2) Adrenal Hemorrhage (d/t Anticoagulants or 2ndry to N. Meningitidis)
3) Infection: Tuberculosis & N. Meningitidis
4) Tumor Metastases to the Adrenal Gland

Question 12

Which form of Adrenal Insufficiency, primary, secondary, or tertiary?

Also, what is the name of a hormone that can replace aldosterone production?

Answer 12

1) Primary (no produciton of Cortisol or Aldosterone)
2) Fludrocortisone

Question 13

What is Conn’s Syndrome?

Answer 13

Adenoma of the Adrenal Cortex; releases excess Cortisol and Aldosterone

Question 14

What is the rate limiting step in the synthesis of Catecholamines?

Answer 14

Tyrosine –> L-DOPA (via Tryosine Hydroxylase)

Question 15

What is the purpose of circulating chromogranins?

Answer 15

They reduce the osmotic burden of storing Epi in chromaffin granules

Question 16

In non neural tissues; most of the catecholamines will be degraded via what enzyme?

Answer 16

COMT

Question 17

In neural tissues the most prominent mechanism of catecholamine degradation occurs via what enzyme?

Answer 17

MOA (Monoamine Oxidase)

Question 18

What are the receptor affinities for the catecholamines in regards to B2, B1, and the rest of the receptors?

Answer 18

B2: High Affinity for Epi

B1: Equal Affinity

Rest: Higher affinity for NORI