Adrenal Gland

Question 1

what is the embryological origin of the adrenal cortex and what does it secrete?

Answer 1

mesoderm

glucocorticoid and androgens (zona fasciculata and reticularis) and mineralcorticoid (zona glomerulosa)

Question 2

what happens if you lose adrenal cortex function?

Answer 2

you die

Question 3

what is the adrenal medulla derived from and what does it secrete?

Answer 3

neural crest cells

epinephrine, norepinephrine, dopa and dopamine

Question 4

what is the precursor of all adrenal cortical hormones? what family of enzymes makes the hormones?

Answer 4

cholesterol

cytochrome P 450 oxidases

Question 5

which enzyme in steroid hormone synthesis is not a cytochrome P450 oxidase?

Answer 5

3 beta- hydroxysteroid dehydrogenase

Question 6

what is the rate limiting step in steroid hormone synthesis?

Answer 6

cholesterol -> pregnenolone

Question 7

what is secretion of aldosterone limited by?

Answer 7

the rate that the glomerulosa cells can synthesize it (not stored)

Question 8

how does aldosterone travel in the blood and what does it do?

Answer 8

travels free (30%) or bound to CBG and albumin
stimulates kidney, colon, salivary glands and sweat glands to reabsorb sodium and water and enhances K secretion

Question 9

how does aldosterone change the electrolyte balance?

Answer 9

by increasing the transcription of Na/K pump and expression of apical sodium channels

Question 10

describe cortisol transport in plasma

Answer 10

most bound to CBT (cortisol binding protein), little bound to albumin and only 3% is free in sln

Question 11

what are two adrenal androgens. how do they compare to testosterone?

Answer 11

DHEA and androstenedione

less potent than testosterone but can be converted to it

Question 12

what is the female implication of DHEA?

Answer 12

it maintains the sex drive of females after menopause

Question 13

how does cortisol demonstrate feedback inhibition?

Answer 13

it inhibits the expression of CRH receptor and ACTH in corticotrophs

Question 14

what is the mechanism of action of cortisol?

Answer 14

it migrates into the nucleus and alters transcription by binding to a transcription factor

Question 15

what are the metabolic effects of cortisol?

Answer 15

stimulates gluconeogenesis, proteolysis, lipolysis and decreases osteoblastic activity in trabecular bone and interferes with Ca absorption in the gut
causes central fat deposition

Question 16

what are the anti inflammatory effects of cortisol?

Answer 16

inhibits cytokines and chemokines production, stabilizes lysosomal enzymes, and contributes to vasoconstriction and decreased capillary permeability

Question 17

what are the immunosuppressive effects of cortisol?

Answer 17

decreased lymphocyte proliferation and inhibits hypersensitivity reaction

Question 18

what are other effects of cortisol?

Answer 18

causes emotional instability

Question 19

what is the cellular action of CRH?

Answer 19

increases cyclic AMP> PKA activation> CRH vesicular release

Question 20

what is the cellular action of ACTH?

Answer 20

cAMP> PKA> increased synthesis of cytochrome P450 and stimulates the rate limiting step in cortisol formation

Question 21

what is pro-poiomelanocortin?

Answer 21

the precursor for ACTH
post translationally processed to ACTH and beta- lipotrophin
during fetal life and pregnancy- yields different hormones

Question 22

when are cortisol levels the highest? the lowest?

Answer 22

highest in the morning and lowest in the evening

Question 23

how is the diurnal cycle of cortisol levels controlled?

Answer 23

light information is transmitted to the suprachiasmatic nucleus of the hypothalamus which controls CRH levels

Question 24

what is the most common form of congenital adrenal hyperplasia?

Answer 24

21 alpha hydroxylase deficiency
decreased production of cortisol and aldosterone
increased production of androgens

Question 25

why is there adrenal hyperplasia with the deficiency of cortisol and aldosterone?

Answer 25

there is no negative feedback to the pituitary so an abundance of ACTH is released-trophic factor for the adrenal gland

Question 26

how is 21 alpha hydroxylase deficiency diagnosed?

Answer 26

elevation of 17-hydroxyprogesterone before and after ACTH stimulation tests. confirmed with genetic analysis of the gene

Question 27

how is 21 alpha hydroxylase deficiency treated?

Answer 27

glucocorticoids provide the negative feedback for ACTH and mineralcorticoids are given if there is elevated renin or infants with salt wasting

Question 28

what is caused by 17- alpha hydroxylase deficiency?

Answer 28

reduced cortisol and androgen synthesis with increased corticosterone and aldosterone reduced estrogen synthesis

Question 29

what are the clinical signs of 17- alpha hydroxylase deficiency?

Answer 29

hypertension, hypokalemia, sexual infantilism in males and females and pseudohermaphroditism in males

Question 30

how is 17- alpha hydroxylase deficiency treated?

Answer 30

hypertension and mineralcorticoid excess- glucocorticoids | females need estrogen treatment. males may need surgery or testosterone treatment

Question 31

what is cushing's syndrome?

Answer 31

hyperadrenal function- excess cortisol for a long time due to any cause

Question 32

what causes cushing's syndrome?

Answer 32

prolonged use of immunosuppression drugs, adrenal tumors and tumors that increase ACTH

Question 33

how is cushing's syndrome different from cushing's disease?

Answer 33

cushing's syndrome refers only to elevated cortisol levels. cushing's disease refers to hypercortisolism secondary to excess production of adrenocorticotrophin from a pituitary gland adenoma

Question 34

what are the symptoms of cushing's syndrome?

Answer 34

moon face, upper body obesity, red complexion, increased fat around the neck and thinning arms and legs. osteopenia, increased infections, glucose intolerance and hypokalemia and hypertension

Question 35

what is the dexamethasone supression test?

Answer 35

dexamethasone is a glucococrticoid that should inhibit ACTH release. given a night time dose and the serum cortisol levels and ACTH are measured in the morning determines between adrenal and ACTH producing tumor depending upon if ACTH is low or high

Question 36

what is another test for cushing's disease?

Answer 36

24 hour urinary cortisol measurements or saliva sampling

Question 37

if a pituitary tumor is suspected, what other tests should be done/

Answer 37

levels of other pituitary hormones

Question 38

what is the treatment for cushing's disease?

Answer 38

surgery to remove the adrenal or ACTH producing adenoma. replace cortisol if both adrenals are removed or can inhibit cortisol synthesis with limited efficacy

Question 39

what is Addison's disease?

Answer 39

hypoadrenal function- failure to produce enough cortisol | primary adrenal insufficiency also deficient in aldosterone

Question 40

what are many of the symptoms of Addison's disease attributed to?

Answer 40

reduced aldosterone synthesis- hyperkalemia

Question 41

what is the most common cause of Addison's disease?

Answer 41

autoantibodies directed against adrenal cells containing 21-hydroxylase (in cortisol and aldosterone synthesis)

Question 42

how is Addison's disease diagnosed?

Answer 42

test cortisol levels, do ACTH stimulation test and CRH stimulation tests positive if there is appropriate ACTH response but low cortisol levels

Question 43

what is the treatment for Addison's disease?

Answer 43

replacing cortisol and aldosterone if necessary