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Regulatory Physiology and Pharmacology > The Adrenal Gland > Flashcards

Flashcards in The Adrenal Gland Deck (107)
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1

What is the adrenal gland?

a hybrid gland consisting of a cortex and a medulla

2

What is important about the hormones of the adrenal gland?

regulators of metabolism and adaptation to stress

3

What is cortisol?

glucocorticoid which increases plasma glucose levels

4

What is aldosterone?

mineralocorticoid promotes salt and water retention by the kidney

5

What else is secreted by the adrenal cortex?

weak androgens which can be converted to testosterone

6

What are the products of chromaffin cells?

epinephrine but also produces small amounts of norepinephrine

7

What are steroid hormones derived from?

cholesterol - different ring structures and side chains

8

What is the common features of steroid hormones?

lipid soluble so are freely permeable

9

How are steroid hormones are carried in the blood ?

complexed to binding globulins - corticosteroid binding globulin binds cortisol

10

Where are the enzymes that produce steroids from cholesterol?

in the mitochondria and smER

11

What are the sources of free cholesterol in the cell is maintained relatively constant?

cellular synthesis of cholesterol from acetate
LDL -> esterified cholesterol from LDL droplets inside the cell

12

What is the rate limiting step in steroidogenesis?

the transport of free cholesterol from the cytoplasm to the mitochodria

13

How is cholesterol carried into the mitochondria?

Steroidgenic Acute Regulatory Protein (StAR)

14

What is cholesterol converted to in the inner membrane?

pregnenolone by CYP450scc -side chain cleavage aka desmolase

15

Where does cholesterol conversion occur?

in the adrenal, ovary and testis

16

What converts pregnenolone to 17a-hydroxypregnenolone?

CYP17

17

What converts pregnenolone and pregesterone to mineralocorticoids?

CYP11B2

18

Where is CYP17 found?

not in glomerulosa

19

Where is CYP11B2 found?

only in the glomerulosa

20

What is synthesised in the fasiculata?

cortisol

21

Which enzyme esterifies free cholesterol?

acyl coA cholesterol transferase

22

Which enzyme turns lipid droplets back into cholesterol?

hormone sensitive lipase

23

What increases the activity of hormone sensitive lipase?

ACTH

24

How many reactions modify cholesterol to cortisol?

5

25

What is the first enzyme in the modification of cholesterol to cortisol and where is it located?

CYP11A1
inner mitochondrial membrane

26

How is the activity of StAR increased?

ACTH stimulates Gs -> cAMP-> PKA which phosphorylates StAR

27

How is cortisol predominantly transported in the blood?

CBG - 90%
albumin - 5-7%

28

What does the unbound form of cortisol do?

exerts its effects on tissues and feedsback on the pituitary and hypothalamus

29

What does the liver conjugate cortisol with?

gluconoride or sulfate

30

What is the circulating half life of cortisol?

70mins