Physio of the Adrenal Cortex Flashcards Preview

Week 27: Adrenal Dysfunction > Physio of the Adrenal Cortex > Flashcards

Flashcards in Physio of the Adrenal Cortex Deck (15)
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What are glucocorticoids predominantly prescribed for?

Anti-inflammatory/immunosuppressive agents
Effects leukocyte movement and function, decrease migration of inflammatory cells to the site of the injury, decreases prostaglandin production


Adrenal gland structure

Cortex and medulla
Cortex has 3 layers" zona glomerulosa, zona fasiculata, zona reticularis


What does each layer of the adrenal cortex produce?
What does the medulla produce?

Glomerulosa: mineralocorticoids (aldosterone)
Fasiculata: Glucocorticoids (cortisol)
Reticularis: androgens
Medulla: catecholamines


Cholesterol for steroid hormone biosynthesis comes from what 2 souces

Circulating cholesterol (major source)
De novo synthesis from acetate


Why can't cells of the zona glomerulosa make cortisol or androgens?

Do not express 17a hydroxylase


Why can't cells of the zona fasiculata and reticularis make aldosterone?

Do not express aldosterone synthase


What type of receptors do steroids have?

Nuclear receptors
They are lipid soluble so their receptors are intracellular
Bind to a hormone response element on DNA and cause gene transcription


How are steroid hormones metabolized

Inactivation mainly occurs in the liver, but also in the target tissues and kidney
Get converted to hydrophilic compounds
Eliminated as urinary metabolites (not recycled)


Aldosterone function

Binds to the mineralocorticoid receptor to regulate gene expression and induce rapid effects via non genomic mechanisms
Regulates reabsorption of Na and secretion to K to maintain blood volume and BP
Production is stimulated by AII


Functions of aldosterone
1. Rapid effects
2. Slower responses

1. Increased Na channel activity in CT and DCT (increasing availability/opening channels)
2. Upregulation of genes for Na channels, Na/K pumps, and kinases


ACTH acts on the cells of the adrenal cortex by what receptor?

Melanocortin-2 receptor


ACTH action

Increases steroidogenesis
Maintains adrenocortical cells
Regulates adrenal androgen secretion


What is the inactive form of cortisol?



Does D1 or D2 enzyme activate or inactive cortisol?

D1: converts inactive to active (liver)
D2: converts active to inactive (kidney)


Glucocorticoid effects on the
1. Liver
2. Muscle
3. Adipose tissue

Maintenance of blood glucose levels
1. Increased hepatic glucose production (gluconeogenesis, glycogen deposition)
2. Decreased glucose uptake, catabolism of protein
3. Lipolysis is stimulated