Biochem 3: Adrenals Flashcards

1
Q

cholesterol derivative hormones are what type of hormones

A

steroid hormones

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2
Q

in which part of the adrenals are steroid hormones made

A

the cortex

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3
Q

Which hormones are created where in the adrenal cortex?

A

Zona glomerulosa: mineralocorticoids (aldosterone)
Zona fasciculata: glucocorticoids (cortisol)
Zona reticularis: androgens (DHEA

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4
Q

What type of hormones are located in the medulla, name the 3 hormones too?

A

catecholamines from tyrosine

NE, Epi, Dopamine

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5
Q

Explain how ACTH is important in synthesis of adrenal cortex hormones

A

Starts the cascade effect of hormone production when ACTH (released from AP) acts on the Gs (cAMP) receptor

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6
Q

What is the cascade effect in synthesis of adrenal cortex hormones

A

ACTH bind to Gs receptor –> activate PKA –>activate lipase.

Lipase then cleaves cholesterol esters to free cholesterol.

Free cholesterol is converted to the different hormones via mitochondrial reactions

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7
Q

what are steroid carrying proteins

A

proteins that are important in transporting steroid hormones to distant sites

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8
Q

why are steroid carrying proteins so important

A

steroid hormones are hydrophobic and so they must be attached to a protein

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9
Q

GIve an example of steroid carrying proteins

A

Cortisol binding protein/globulin
it carries:
1.cortisol
2. aldosterone

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10
Q

CBP is produced in the adrenals TRUE or FALSE

A

FALSE; they are produced in the liver

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11
Q

whats the point of cortisol-cortisone shunt

A

to prevent cortisol from binding to mineralocorticoid receptor (MR)

the concentration of cortisol is 1000x greater than aldosterone, which allows it to easily bind with MR causing AME

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12
Q

What happens when cortisol binds with MR

A

Apparent mineralocorticoid excess (AME)

  • Conn Syndrome like effect – hyper-aldosteronism
  • cortisol can activate MR so with a 1000x concentration of cortisol, its going to active it
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13
Q

what 2 hormones can bind to MR

A

cortisol and aldosterone

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14
Q

So how does the shunt prevent cortisol from binding with MR

A

converts cortisol into cortisone

cortisone can’t bind with MR receptor.

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15
Q

what 2 enzymes are involved in activating and inactivating cortisol

A

11B-HSD2 - inactivator of cortisol in the KIDNEY (cortisol–> cortisone)

11B-HSD1 - activator of cortisol in the LIVER (cortisone–>cortisol)

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16
Q

what is so special about the skin

A

has 11B-HSD1; allows cortisone cream to convert to cortisol (active form)

Thats why topical is effective

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17
Q

What is interesting about licorice

A

contains glycyrrhizic acid which INHIBITS 11B-HSD2.

this allows cortisol access to MR which leads to HTN and hypokalemia

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18
Q

What is the role of CYP450 in steroid hormones

A

convert free cholesterol to metabolite pregnenolone

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19
Q

Pregnenolone is needed …

A

for the production of all steroids: mineralocorticoids, glucocorticoids, androgens

20
Q

which enzyme catalyzes cortisol and androgen

A

CYP17

21
Q

which hormones do CYP21 catalzye

A

cortisol and mineralocorticoids

22
Q

TRUE or FALSE; if theres a deficiency in one of the enzymes it will shift production of steroids to the other pathway

A

TRUE

if CYP21 is deficient –> coritsol and mineralocorticoid isn’t produced but since CYP17 still works androgen will be produced

23
Q

TRUE or FALSE; cortisol needs either pathway to work in order to be produced

A

FALSE; it needs the activity of BOTH CYP17, 21 (and 11)

24
Q

what is Cushing Syndrome

A

excess cortisol for any reason

25
Q

what is Cushing Disease

A

limited to pituitary adenoma –> increased ACTH levels

26
Q

Cushing Syndrome can be classified on LOCATION OF PRODUCTION

A

Endogenous: w/in the hypothal, pit, or adrenal axis

Exogenous: source outside the body (DRUGS)

27
Q

Cushing Syndrome can be classified on LOCATION OF LESION

A

Primary: abnl in the ADRENAL gland –> increased cortisol prodcution

Secondary: abnl in the PITUITARY gland –> increased cortisol level
- typically by increasing ACTH levels

28
Q

What are the 4 symptoms of Cushing Syndrom

A
  1. HTN
  2. Weight gain
  3. Wound
  4. Muscle wasting
29
Q

What is Addison Disease

A

progressive destruction of adrenal gland —> decreasing steroid synthesis

30
Q

What will you see with the hormone levels

A

LOW cortisol and aldosterone

31
Q

What are the symptoms of Addison Disease

A

Hyperpigmentation
Hyponatremia
Hyperkalemia

32
Q

Explain how hyperpigmentation arises in Addison

A

low cortisol levels –> increase ACTH levels

ACTH release is associated with increases in MSH –> increased MSH –> hyperpigmentation

33
Q

which hormone is responsible for hyponatremia and hyperkalemia in Addison

A

Low Aldosterone

34
Q

What is congenital adrenal hyperplasia

A

a block in corticosteroid synthesis bc of defect in CYP21 –> leading to shunting into ANDROGEN (CPY17)

increased androgen

35
Q

what are the symptoms of CAH

A

virilization in females –> too many androgens (ambiguous genitalia)

hyperkalemia, hyponatremia, and wegith loss –> NO ALDOSTERONE –> salt and water loss

36
Q

what is apparent mineralocorticoid excess (AME)

A

cortisol binds to MR –>mimics high ALdosterone levels –> hypokalemia, hypernatremia –> HTN

37
Q

which enzyme is defective in AME

A

11B-HSD2 in the kidney (cortisol –> cortisone)

38
Q

How are catecholamines synthesized

A

phenylalanine –> L-Tyrosine –> Dopa –> Dopamine –> NE –> Epi

39
Q

TRUE or FALSE: neurons make both NE and Epi

A

FALSE; neurons make up to NE and ADRENAL MEDULLA makes Epi

40
Q

what 2 enzymes metabolize catecholamines

A

MAO (monoamine oxidase)

COMT (cathechol -O-methyl transferase)

41
Q

what do the catecholamine eventually break down to

A

vanillylmandelic acid, VMA

aka 3-methoxy-4-hydroxymandelic acid

42
Q

where can you find VMA

A

excreted in the urine and also seen in teh blood

43
Q

what is pheochromocytoma

A

benign enlargements of the medullary adrenal gland –> increases syn of catecholamine (uncontrolled)

44
Q

what are the symptoms of pheo

A
HA
HTN
palpitation
tremor
diaphoretic
45
Q

how do you diagnose pheo

A

find elevated VMA in teh urine