Adrenal Medulla

Question 1

What is the enzyme in the adrenal medulla that converts NE into Epi?

Answer 1

PNMT phenylethanolamine- N-methyltransferase

Question 2

What are the metabolic end products of catecholamines?

Answer 2

metanephrines and (VMA) vanillylmandelic acid

Question 3

What are the effects of epinephrine on the liver?

Answer 3

epi increases the acivity of the liver and muscle phosphorylase, promoting glycogenolysis

Question 4

What are the effects of epi on sk. muscle?

Answer 4

Epinephrine promotes glycogenolysis but because muscle lack glucose-6-phosphatase, glucose cannot be released by sk. muscle; instead, it must be metabolized at least to lactate before being released into the circulation

Question 5

What are the effects of epi on adipose tissue?

Answer 5

increases lipolysis in adipose tissue by increasing the activity of hormone sensitive lipase

Question 6

What are pheochromocytomas?

Answer 6

adrenal tumors that secrete epi and NE in various ratios they are usually unilateral and benign

Question 7

What is the most consistent features of pheochromocytomas?

Answer 7

HTN, increased metabolic rate and hyperglycemia also occur

Question 8

What is the most reliable initial test for pheochromocytomsas?

Answer 8

plasma metanephrines or 24 hour urine catecholamines or metanephrines

Question 9

How does Epi stimulate increased lipolysis?

Answer 9

increases activity of hormone-sensitive lipase in adipose tissue