COUNTER REGULATORY HORMONES

Question 1

Function of counter regulatory hormones?

Answer 1

Counteract the storage functions of insulin in regulating blood glucose levels during periods of fasting, exercise, stress
- either limit glucose intake or deplete glucose stores

Question 2

What are the counter regulatory hormones?

Answer 2

1. Epinephrine
2. Growth hormone
3. Glucocorticoids (specifically cortisol)
4. Glucagon

These hormones play an essential role in glucose homeostasis, especially in times of stress and hypoglycaemia

Question 3

Epinephrine:

Answer 3

• Is a catecholamine released by adrenal medulla when stimulated by the sympathetic nervous system (active in stress response)
• causes transient hyperglycaemia by promoting gluconeogenesis and glycogenolysis in the liver
• in skeletal muscle, it inhibits glycogen formation and accelerates glycogen breakdown
• inhibits insulin release from beta cells which decreases glucose uptake in muscles and other organs (preserves glucose for brain)
• stimulates lypolysis by freezing triglycerides and fatty acids from adipose tissue
• inhibits degradation of circulating cholesterol to bile acids

Question 4

Growth Hormone:

Answer 4

• increases protein synthesis in all cells of the body, stimulates lipolysis and antagonizes the effects of insulin
• decreases cellular uptake and use of glucose
  -“acromegaly” - characterized by hyper secretion of growth hormone can result in glucose intolerance or development of DM
• ppl with diabetes, increase in growth hormone which occurs in periods of stress and growth for children can lead to the whole spectrum of metabolic abnormalities, goes with poor regulation even tho insulin treatment may be optimized

Question 5

Glucocorticoids (cortisol)

Answer 5

• refers to steroid hormones that have direct effect on carb metabolism
• one of the main effects of cortisol is to stimulate gluconeogenesis
• decrease use of glucose by tissues
• any type of stress causes release of corticotropin releasing hormone (CRH) from hypothalamus, which stimulates anterior pituitary gland to release adrenocorticotropic hormone (ACTH) which signals adrenal gland to increase secretion of cortisol
• outside the liver, glucocorticoids stimulate protein catabolism and inhibit amino acid uptake and protein synthesis
• increased cortisol complicates diabetes