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38 Cards in this Set
- Front
- Back
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What are the types of hormones the adrenal cortex secretes? (3)
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Adrenal Corticosteroids:
1. Glucocorticosteroids 2. Mineralocorticoids 3. Androgens |
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What is the function of glucocorticoids?
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Counter-regulatory to insulin
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What is the major glucocorticoid?
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Cortisol
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What is the major mineralocorticoid?
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Aldosterone
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What is the major adrenal androgen?
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Dehydroepiandrosterone (DHEA) (& androstenedione)
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Cortisol has what effect on blood glucose?
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Elevates blood glucose:
Promote gluconeogenesis |
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Cortisol has what effect on muscle protein & protein synthesis? (3)
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1. Inhibits protein synthesis
2. Sitmulates breakdown of muscle protein 3. Amino acids avialable for liver gluconeogenesis |
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Cortisol has what effect on liver? (2)
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1. Synthesis of gluconeogenc enzymes in liver
2. Increases glycogen deposition & glucose release by liver |
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Cortisol is pleiotropic, what does that mean?
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It acts on many systems
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What are cortisol's pleotrorpic effects? (7)
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1. Increase total WBC count
2. Increase resistance to stress 3. Increase total body fat 4. Increase water excretion 5. INcrease brain activity 6. Decrease immune system function 7. Decrease inflammation |
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In general terms, what are cortisols pleiotropic effects?
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Protects from over-reaction from stress & has anti-inflammatory response
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What is one way that glucocorticoids aid in anti-inflammatory response?
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Inhibit breakdown of membrane phospholipids to from arachodonic acid & prostaglandins
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Glucocorticoids act through what type of messenging?
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Cytoplasmic receptors which are bound to heat shock proteins & when hsp are released they form hormone-receptor complex dimers that affect gene expression
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What parts of the body does aldosterone act on?
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1. Distal convoluted tubule of kidneys
2. Sweat glands 3. Intestinal mucosa |
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Action of aldosterone? (2)
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1. Increase Na retension
2. Increase K excretion |
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Adrenal androgens have opposite action of which hormone?
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Opposite action of cortisol:
ANABOLIC-- increase protein synthesis |
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What may assist in pubertal growth spurt of females?
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Anabolic action of adrenal androgens
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Adrenal androgens (androstenedione) serve as a substrate for?
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Estrogen synthesis in adipose tissue & estrogen-secreting endocrine glands
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What is the committed step in steroid hormone synthetic pathways?
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Cholesterol --> Pregnenolone
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What pathway resides in zona glomerulosa?
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Pregnenolone --> Progesterone --> Aldosterone
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What pathway resides in zona fasciculata?
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Pregnenolone --> Progesterone --> 17-hydroxy-progesterone --> Cortisol
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Which pathway resides in zona reticularis?
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Pregnenolone --> 17-hydroxysteroid precursors --> Dehydroepandrosterone & Andorstenedione
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Which steroid hormones are 17-ketosteroids?
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1. Dehydroepandrosterone
2. Androstenedione |
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Cortisol is bound to which proteins in blood? (2)
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1. CBG or transcortin (mostly)
2. Albumin |
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What elevates the amount of transcortin in plasma?
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Female sex hormones (estrogens)
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What lowers amount of transcortin in plasma? (3)
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1. Liver disease
2. Amyloid disease 3. Multiple myeloma |
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Aldosterone in blood is mostly bound to?
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Albumin
(small amount bound to transcortin) |
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Dehydroepiandosterone & androstenedione are mostly bound to?
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Albumin
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What portion of hormones is responsible for biological effects?
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Free hormones in plasma (10%)
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Where are steroid hormones broken down to inactive metabolites?
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Peripheral tissues & liver
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To inactivate steroid hormones they are first converted to?
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Inactive tetrahydro-deratives
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Inactive tetrahydro-derivatives are then conjugated to?
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Glucuronic or sulfuric acids & excreted in urine
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Corticotropin releasing hormone CRH is secreted by?
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hypothalamus
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CRH stimulates what?
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CRH stimulates anterior pituitary to release ACTH
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ACTH stimulates?
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Conversion of cholesterol --> Pregnenolone --> synthesis of all adrenal corticosteroids
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How is corticol secretion regulated?
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Cortisol feeds back on hypothalamus & anterior pituitary to reduce secretion of CRH & ACTH
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ACTH secretion undergoes?
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Diurinal variation
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ACTH peaks during?
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late sleep (diurnal variation)
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