Hormones of the Adrenal Glands

HPA Axis

• Hypothalamus releases CRH to the Ant. Pituitary which releases ACTH to the adrenal cortex which releases cortisol

• Cortisol inhibits the release of CRH and ACTH

Mineralocorticoids

• Aldosterone

• Synthesized in zona glomerulosa

• Regulates mineral balance in blood versus urine

• Incresase water retention through blood volume and serum Na+

• Increases urine excreation of K⁺ and H⁺

• More H2O and Na²⁺, less K⁺ and H⁺

• Also interacts with angiotensis-renin system

  • ACE and ACE inhibitors for hypertension

HPA Axis

• Hypothalamus releases CRH to the Ant. Pituitary which releases ACTH to the adrenal cortex which releases cortisol

• Cortisol inhibits the release of CRH and ACTH

Mineralocorticoids

• Aldosterone

• Synthesized in zona glomerulosa

• Regulates mineral balance in blood versus urine

• Incresase water retention through blood volume and serum Na+

• Increases urine excreation of K⁺ and H⁺

• More H2O and Na²⁺, less K⁺ and H⁺

• Also interacts with angiotensis-renin system

  • ACE and ACE inhibitors for hypertension

Glucocorticoids

• Cortisol

• Long-term stress response

• Released at highest levels in early morning

• Also released during hypolycemia and exercise

Cortisol

• increases blood glucose during stress

• stimulates gluconeogenesis

• inhibits insulin-dependent glucose uptake in muscle and fat

• stimulates food intake

• stimulates GI motility, secreation of gastric H+ and pepsin

• Stimulaties lipolysis (fat breakdwon)

• stimulates proteolysis (result = muscle wasting)

  • Reduces inflammatory and immune response

What are the effects of cortisol on various systems?

What are OTC and prescription glucocorticoids?

• Primarily used to reduce immune response and inflammation

  • Allergy medicines

  • Hydrocortisones

  • Predinosenes

  • IBS treatments

  • Arthritis treatments

  • MS (slows myelin sheath loss)

• Powerful and commonly prescribed

• MUST watch side effects and dosage

Androgens

• Stimulated by ACTH release

• Androgens act as precursors to estrogen or testosterone

• Testosterone is converted to DHT (5alpha-reductase)

• Testosterone converted to estrogen (aromatase)

• Supplement gonadal hormones

Catecholamines

• Epinephrine

• Norepinephrine

• Short term stress response

  • flight or fight

• Increased blood glucose

• Increased vasodilation and blood oxygen

  • Muscles, lungs, brain

• Decreased vasodilation

  • Gut, kidneys, etc

• Released from chromaffin cells in medulla

• Sympathetic nervous system