Glucocorticoids

Question 1

What is the pattern of glucocorticoid synthesis and release?

Answer 1

not stored in the adrenal gland but synthesised under the influence of circulating ACTH secreted from the anterior pituitary gland
releasedin a pulsatile fashion into the blood
there is a well defined circadian rhythm with blood concentration reaching a high early in the morning and diminishing throughout the day and reaching a low point in the evening or night

Question 2

What is the precursor of glucocorticoids?

Answer 2

cholesterol

Question 3

What is the rate limiting step in the conversion of cholesterol to glucocorticoids?

Answer 3

the first step
cholesterol –> pregnenolone
regulated by ACTH

Question 4

What are some common glucocorticoid drugs?

Answer 4

hydrocortisone, prednisolone, dexamethasone

Question 5

What are the main metabolic effects of glucocorticoids?

Answer 5

decrease in the uptake and utilisation of glucose and an increase in gluconeogenesis - tendency for hyperglycaemia
concomitant increase in glycogen storage which may be a result of insulin secretion in response to the high levels of glucose
increased protein breakdown –> tissue wasting
redistribution of fat