Adrenocortical Hormones Flashcards

1
Q

What type of hormone is cortisol?

A

Steroid Hormone

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2
Q

Where is cortisol produced?

A

Adrenal Gland (Zona Fasciculata)

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3
Q

Cortisol is an example of a …

A

… glucocorticoid/corticosteroid

Glucose Metabolism

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4
Q

Cortisol production is dependent on …

A

… adrenocorticotropic hormone (ACTH)

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5
Q

What are the steps of cortisol production?

A

Synthesis of cholesterol
Mitochondrial Conversion
Smooth ER

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6
Q

Which receptors does cortisol bind to?

A

Glucocorticoid Receptors (GRs)

Most cells have a GR

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7
Q

How is cortisol transported?

A

90% bound to corticosteroid-binding globulin (CBG)
3% free in the plasma

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8
Q

Another name for cortisol bound to CBG is …

A

… transcortin

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9
Q

Which cortisol can enter the cell?

A

Free cortisol

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10
Q

In which condition does total cortisol and CBG increase?

A

During pregnancy

Note free cortisol does not increase. The patient shouldn’t show signs of high cortisol

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11
Q

What are the effects of cortisol?

A

Glucose and overall metabolism
Immune system
Cognition
Bone formation
Fetal Development

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12
Q

What are the metabolic effects of cortisol?

A

Increases energy-generating substances

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13
Q

What are some energy-generating substances which cortisol can generate?

A

Glucose
Glycerol
Amino-acids

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14
Q

How does cortisol increase serum glucose?

A

Increases Gluconeogenesis
Decreases Glycogen Formation
Reduces Glucose Uptake
Decreases Insulin Secretion
Increases Glucagon Secretion

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15
Q

How is glycerol generated?

A

Increased lipolysis

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16
Q

How are amino acids generated?

A

Increased proteolysis

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17
Q

In addition to increasing glycerol, glucose and amino acids in blood, cortisol also decreases …

A

… protein synthesis and peripheral amino acid uptake

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18
Q

What is Cushing Syndrome?

A

High cortisol level

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19
Q

What are the effects of Cushing Syndrome?

A

Person develops insulin-resistant diabetes

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20
Q

Cortisol can upregulate the number of ____ receptors on arterioles

A

____ vasoconstricting α1 ____

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21
Q

How can vasopressin increase blood pressure?

A

Cortisol activates mineralocorticoid receptors
Increases sodium reabsorption and blood volume

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22
Q

Does MR have a higher affinity for cortisol or aldosterone?

A

Same affinity

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23
Q

How is cortisol mineralocorticoid signaling regulated?

A

MR is protected from cortisol by 11β-dehydrogenase isozyme 2

Since cortisol levels are 100 times higher than aldosterone, it is important that this enzyme functions to ensure that cortisol reactions are not uncontrolled

24
Q

What effect does 11β-dehydrogenase isozyme 2 have on cortisol?

A

Metabolizes it to inactive form

25
Q

What effect does cortisol have on immunity and wound healing?

A

Cortisol decreases inflammation, immunity and wound healing

26
Q

Why does cortisol reduce inflammation and immunity?

A

Acts as an anti-inflammatory molecule

27
Q

Which chronic inflammatory conditions can cortisol be used in?

A

Skin rashes
Inflammatory kidney diseases

28
Q

What are some additional cortisol functions?

A

Decreasing bone formation
Modulation of fetal lung development
Stimulates cognition and memory
Decreases osteoblast activity

29
Q

How does cortisol modulate fetal lung development?

A

Production of surfactant

30
Q

Why is cortisol given to mothers giving birth prematurely?

A

Steroid cross the placenta and hasten fetal lung development

31
Q

How does cortisol stimulate cognition and memory?

A

Terminal maturation
Axon remodeling

32
Q

Patients taking glucocorticoid drugs are at risk of …

A

… osteoporosis

33
Q

Which regions of the brain does cortisol impact?

A

Hippocampus
Amygdala
Frontal Lobes

34
Q

What effect does cortisol have on formation of memories?

A

Reinforces strong memories (good and bad)

35
Q

What effect does cortisol have on cognition?

A

Development of alertness and cognition

36
Q

What effect does cortisol have on fibroblast activity?

A

Decreases

37
Q

Definition of stress

A

Any noxious stimulus increase ACTH

38
Q

Describe the pathway of cortisol secretion

A

Stress → Paraventricular Nucleus → Limbic System → Hypothalamus (CRH) → ACTH (anterior pituitary) → Cortisol

39
Q

Functions of mineralcorticoids/aldosterone

A

Critical for maintaining blood pressure

40
Q

How can aldosterone increase blood volume?

A

Increases sodium reabsorption
Excretes excess potassium

41
Q

Where is aldosterone produced?

A

Zona glomerulosa (outermost layer) of adrenal gland

42
Q

What is the rate limiting enzyme in aldosterone synthesis?

A

Steroidogenic Acute Regulatory Protein(StAR)

43
Q

Aldosterone transport

A

50% bound to serum albumin
30% circulates freely in blood
17% binds to CBG (also called transcortin)

Transcortin binds to cortisol and progesterone

44
Q

Pathway of aldosterone affecting cells

A
45
Q

How can MR and aldosterone affect transcription?

A

MR is a ligand-dependent transcription factor (TF)
Aldosterone bound to receptor acts as TF

46
Q

What chemical can inhibit corticosteroid 11β-dehydrogenase isozyme 2?

A

Chemicals found in genuine licorice

47
Q

What can inhibition of corticosteroid 11β-dehydrogenase isozyme cause?

A

Pseudohyperaldosteronism

The name is because mineralocorticoid effects are not caused by aldosterone, but instead by circulating cortisol that can now bind and activate the MR

48
Q

What are the effects that aldosterone has on the kidneys?

A

Sodium reabsorption
Potassium excretion
Secretes H+ into tubular fluid

49
Q

How does aldosterone increase sodium reabsorption?

A

Increases sodium channels on the lumen side of the cell
Na+/K+ ATPase pump on basolateral to move sodium into interstitial blood

50
Q

How does aldosterone increase potassium excretion?

A

Na+/K+ ATPase pump on basolateral to move potassium into principal cells
Increases potassium channels on lumen side

51
Q

How does aldosterone enable secretion of H+ into tubular fluid?

A

Stimulate H+-ATPase on the ɑ-intercalatedcellsin the collecting duct

52
Q

How can hypertension be caused by primary hyperaldesteronism?

A

Adrenal glands continuously secrete aldosterone
Causes increased sodium and water reabsorption and hypokalemia

53
Q

What are the aldosterone regulators?

A

Angiotensin II
Increased serum potassium
Adrenocorticotopic Hormone

54
Q

How can angiotensin II affect aldosterone?

A

Increases aldosterone secretion through RAAS pathway during low BP

55
Q

How does ACTH affect aldosterone secretion?

A

Affects formation of aldosterone precursors