Adrenal Function, Testing and Disorders

Chemistry CLS 415 Didactics

Ricki Otten, MT(ASCP)SC

Part 2: Cortex Hormone Function and Regulation

Mineralcorticoids: Aldosterone

• Function/Physiologic effects• Na+ and K+ homeostasis• Regulates extracellular fluid

volume through sodium reabsorption by kidneys

• Synthesized only in the adrenal gland: zona glomerulosa

• Major control mechanism: Renin-angiotensin-aldosterone (RAA) system

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Renin: an enzyme

Produced in the juxtaglomerulosa cells of the kidney

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Angiotensin converting enzyme (ACE)

Produced in lung

Angiotensinogen: a protein substrate

Produced in liver

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Angiotensin II:

Potent vasoconstrictor

Stimulates Adrenal Cortex to produce Aldosterone

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6

2

1

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2

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8

2

1

9

2

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Glucocorticoids: Cortisol

Essential for life

Major stress protector

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Glucocorticoids: Cortisol• Function/Physiologic effects

• Influences carbohydrate metabolism:• Promotes gluconeogenesis• Promotes glycogenolysis

• Stimulates protein catabolism (breakdown)• Central distribution of fat: neck, face and trunk• Anti-inflammatory actions• Immunosuppressive actions• Anti-allergic properties

Increase plasma glucose

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Glucocorticoids: Cortisol

• Diurnal variation• Under ACTH influence• Highest cortisol levels

in early am• Lowest cortisol levels

in late pm

• Synthesized in the adrenal gland

• Major control mechanism: Negative feedback control

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Hypothalamus-Pituitary-Adrenal axis

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