Lecture 10 Flashcards
Zona glomerulosa secretory products:
Mineralocorticoids. Mainly aldosterone.
Zone fasciculata secretory products:
Glucocorticoids. Mainly cortisol.
Zone reticularis secretory products:
Androgens.
Size of adrenal glands:
4g each
Secretory products of adrenal medulla: %s
Chromaffin cells secrete E (80%) and NE (10%)
Cortisol: importance in humans, half life
Primary glucocorticoid in humans.
Half-life of 70-90 minutes.
Transport of cortisol:
90% bound to corticosteroid-binding globulin
7% bound to albumin
3-4% free
What tissues contain glucocorticoid receptors?
All nucleated tissues!
Cortisol’s glucose increasing activity:
Enhance protein breakdown to provide liver with AAs to build into glucose and glycogen.
Increase lipolysis and allow additional glycerol into the liver.
Cortisol during starvation:
Essential! Can make glucose from different routes.
Anti-inflammatory activity of cortisol:
Enhance lipocortin and annexin -> inhibit PLA -> inhibit arachidonic acid and its inflammatory babies.
Reduces T-lymphocytes.
Inhibits histamine release and reduces releasers.
Who all does cortisol hate?
Arachidonic acid, cytokines, interleukin-2, T-lymphocytes, histamine, bradykinin, serotonin, eosinophils, basophils
Cortisol and vascular system:
Optimizes responsiveness to catecholamines. Maintains normal blood pressure in arterioles.
Cushing syndrome:
Caused by excess cortisol.
Symptoms: truncal adiposity, hypertension, hyperglycemia, loss of subcutaneous adipose and connective tissue in extremities, loss of bone mineral, muscle weakness/wasting
Adison’s syndrome:
Caused by insufficient cortisol.
Symptoms: chronic adrenal insufficiency, hypocortisolism.
Aldosterone: what is it made of? half-life?
Made from LDLs.
Half-life of 15-20 minutes.
Transport of aldosterone:
Albumin.
Effects of aldosterone:
Control salt/water retention.
Systems for stimulating aldosterone secretion:
Renin-angiotensin system
ACTH system
Potassium system
ACE-inhibiting drugs:
Angiotensin Converting Enzyme turns angiotensin I into angiotensin II, which stimulates aldosterone secretion.
Conn syndrome:
Hyperaldosteronism. Tumour of the zona glomerulosa.
Aldosterone and heart health:
Aldosterone increases fibrosis in myocardium and blood vessel walls.
Locations of adrenergic receptor types:
alpha 1, alpha 2, beta 1, beta 2, beta 3
Alpha 1: most sympathetic target cells
Alpha 2: digestive system
Beta 1: heart
Beta 2: skeletal muscle, vascular and bronchial smooth muscle
Beta 3: adipose tissue, heart and skeletal muscle
Adrenergic receptor affinity for NE/E:
Alphas both like NE better.
Beta 1 likes them equally.
Beta 2 only likes E.
Beta 3 doesn’t like anyone.
Which adrenergic receptors have excitatory response? inhibitory?
Excitatory: odd numbers.
Inhibitory: even numbers.
Degradation of circulating catecholamines:
Catecholamine-O-methyltransferase and monoamine oxidase break them down Real Fast.
Hyp pit adrenocortical axis:
Corticotropin-releasing hormone from hyp -> ACTH from ant pit corticotrophs -> synthesis and secretion of cortisol.
AC pathway.
Regulators of ACTH:
Mainly CRH, slightly vasopressin.
POMC:
Pro-opiomelanocortin. Precursor for ACTH and a bunch of other things.
