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Flashcards in SPR L2 Adrenal Hormones (1) Deck (24):
1

Learning Outcomes

  • List the main hormones produced by the adrenal gland and their functions
  • Describe the circadian rhythm of cortisol and its control by CRH and ACTH
  • List the main actions of glucocorticoids like cortisol
  • Explain the significance of cortisol during major physical stress
  • Compare and contrast control of aldosterone secretion with that of cortisol
  • Describe the mineralocorticoid effects of aldosterone in terms of its renal actions
  • Describe the main effects of glucocorticoid deficiency and excess and explain these in terms of normal hormonal actions
  • Explain how ACTH levels will change with different types of cortisol abnormality
  • Describe the effects of excess or deficient aldosterone in terms of these actions

2

What secretes corticosteroids?

The adrenal cortex 

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3

Name the layers of the Adrenal Cortex

  • Zona Glomerulosa
  • Zona Fasiculata 
  • Zona Reticularis 

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4

What do the following secrete?

  1. Zona Glomerulosa
  2. Zona Fasiculata 
  3. Zona Reticularis 

  1. Mineralocorticoids
  2. Glucocorticoids
  3. Adrenal Androgens

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5

How are the following transported in the blood?

  1. Cortisol
  2. Aldosterone
  3. Adrenal Androgens

  1. 98% bound primarily to corticosteroid-binding globulin (trancortin)

  2. 60% bound primarily to albumin

  3. 98% bound exclusively albumin

6

Where are the following secreted from?

  1. Catecholamines
  2. Androgens
  3. Cortisol
  4. Aldosterone

  1. Medulla
  2. Zona Reticularis (Adrenal Androgens)
  3. Zona Fasiculata (Glucocorticoids)
  4. Zona Glomerulosa (Mineralocorticoids)

 

(some overlap between fas and ret layers in terms of release)

7

Intracellular actions of adrenal steroids

 

Steroid hormones enter cytoplasm, bind to cytoplasmic receptors, create a Hormone-Receptor complex, enter the nucleus and cause a change in gene activity, altering protein syntesis, giving alterations in structural proteins or enzyme activity and resulting in a target cell response.

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8

Glucocorticoids: Regulation of Cortisol Secretion

How is cortisol secretion regulated?

 

Stress (Physical, Emothional, Chemical, Others)

Circadian or Diurnal Rhythm

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9

Outline the actions of Glucocorticoids

  1. Muscle
  2. Liver
  3. Fat Cells
  4. Immune System and Inflammation

  1. Net loss of amino acids (glucose)
  2. Gluconeogenesis (glucose) and glycogenesis
  3. Free fatty acids mobilisation - lipolysis
  4. Suppressed

Generally catabolic, but in the liver, glycogenesis occurs.

10

Cortisol has a role in adaptation to stress 

Cortisol directly promotes rapid supply of glucose to tissues

Cortisol is a ’permissive’ hormone

Give two important actions of Cortisol

 

  1. it effects the other counter-regulatory hormones (see picture) eg. Insulin, glucagon, adrenaline, growth hormone

  2. Cortisol is required for the expression of adrenergic & angiotensin II receptors in the CVS - needs to be present for blood pressure to be normal

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11

Give some causes of Glucocorticoid Excess

  • Hypothalamic tumour
  • Anterior pituitary tumour (Cushing’s Disease)
  • Adrenal tumour
  • Ectopic tumor

12

What syndrome is caused by Glucocorticoid Excess?

Cushing's Syndrome

13

  1. What can secondary hypersecretion of glucocorticoids be caused by?
  2. What can primary hypersecretion of glucocorticoids be caused by?

  1. a hypothalamic problem or pituitary problem
  2. problem with the adrenal cortex

14

What are the following characterised by?

  1. 2ry hypersecretion of glucocorticoids due to a hypothalamic problem?
  2. 2ry hypersecretion of glucocorticoids due to a pituitary problem?
  3. 1ry hypersecretion of glucocorticoids due to a problem with the adrenal cortex
  4. Which of these is Cushing's Syndrome?

  1. High CRH, ACTH and Cortisol Levels
  2. High ACTH and Cortisol Levels, Low CRH Levels
  3. High Cortisol Levels, Low CRH and ACTH Levels
  4. 2. Ant Pituitary Tumour (High ACTH and Cortisol Levels, Low CRH Levels)

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15

Cushing's Syndrome

 ​Give examples of signs and symptoms

(generally)

 

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Abdominal Striae

Central Fat Deposition

Thinning of Limbs

Bruising 

Moon face 

Buffalo Hump

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16

Cushing's Syndrome

​What do the effects on the following give rise to

  1. Carbohydrate Metabolism
  2. Protein Metabolism
  3. What other effects are there?

  1. Hyperglycaemia - increase blood glucose levels x 2 normal “Adrenal diabetes”

  2. Protein shortage - muscle weakness

    Stretch lines, (Striae)

    Easy bruising

    Thinning of Skin

  3. Suppression of the immune system and Osteoporosis

17

Give the symptoms of Cushing's Syndrome 

(with the mneumonic CUSHING)

C - Central obesity, collagen fibre weakness, comedones (acne)

U - Urinary free cortisol and glucose increase

S - Striae, Suppressed Immunty

H - Hypercortisolism, Hypertension, Hyperglycaemia, Hypercholesterolemia

I - Iatrogenic (increased administration of corticosteroids)

N - Noniatrogenic (neoplasms)

G - Glucose intolerance, Growth Retardation

18

Mineralocorticoids: regulation of aldosterone secretion

 

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19

Actions of aldosterone (mineralocorticoid effect)

What are the actions of aldosterone?

  • increased Na+/H2O absorption
  • increased K+/H+ secretion
  • increased blood volume/BP

 

Increased production of ion channels

Increase in production of na/k ATPase

This means that there is increase sodium absorption and K+ secretion 

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20

What does Aldosterone Deficiency lead to?

  • increased loss of Na+ and H2O in the urine - dehydration, plasma depletion and hypotension
  • renal retention of K+ and hyperkalaemia. Increases cardiac excitability and can cause ventricular fibrillation
  • renal retention of H+ producing a metabolic acidosis

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21

What is Primary Hyperaldosteronism?

Conn's Syndrome

Secreting Tumour

Increased Aldosterone

Increased Na+ retention, increased total body Na+, increased ECF

Increased BP - Plasma volume expansion

Decreased Renin

Increased K+ loss

Decreased plasma K+

(secreting tumour)

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22

What is secondary hyperldosteronism caused by?

Overactivity of the Renin-Angiotensin System

23

What are the clinical manifestations of primary hyperaldosteronism?

Hypertension

Hyperkalaemia

Hypervolaemia (without peripheral oedema)

Metabolic Alkalosis

24

What is renal insufficency usually due to?

a problem in the RAAS 

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