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Block 4 Biochem
Hormones
23
Biochemistry
3rd Grade
11/14/2012

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Term
Name for vitamin A?
Definition
-Retinol
Term
Where do we get vitamin A? How do we process it?
Definition
-Mostly from B-carotene
-We cleve it to two molecules of retinol, and then process it to retinoic acid; a hormone for differentiation and growth
Term
Retinoic acid?
Definition
-Derived from vit A
-Functions like a steroid hormone to promote growth and differentiation (esp. of epithelial cells)
Term
Where is GH made?
Definition
-Somatotroph cells of anterior pituitary
Term
Relate GH to insulin?
Definition
-It acts mainly as an antagonist, promoting gluconeogenesis and lipolysis.
-It also promotes glycogen synth, but this is the same as insulin
Term
What are mechanisms of GH control?
Definition
Stimulated by;
-GHRH
-Hypoglycemia
-AAs like arginine
-Prolonged fasting

Inhibited by;
-Somatostatin
-Hyperglycemia
Term
What are IGFs?
Definition
-Insulin-like growth factors stimulated by GH that have more potent growth effects than insulin itself
-There are two IGF-I & IGF-II
-IGF-I is linked to a tyrosine kinase receptor
Term
Acromegaly?
Definition
-Caused by benign tumor of anterior pituitary after closure of epiphyseal plates (after puberty)
-Caused from excess GH secretion
-Causes an enlargement of the jaw, brow, and fingers
Term
Gigantism?
Definition
-Ant. pit benign tumor before end of growth (before puberty)
-Leads to hypersecretion of GH
-Both hypersecretion of GH diseases often lead to diabetes because of high gluconeogenesis
Term
Where is vasopressin produced and stored?
Definition
-Produced in hypothalamus and stored in POST. pituitary
Term
Vasopressin action? Mechanism?
Definition
-aka ADH
-responds to high serum Na or low serum volume to increase water retention
-Leads to PKA and increased aquaporin-2 synth, which let water back in from tubules
Term
ANP? Where from and action? Mechanism?
Definition
-Atrionatriuretic peptide
-Released from atrial cells in heart
-Increases urine output and acts as vasodilator
-Works through a cGMP pathway to activate PKG (Gt path?)
Term
Aldosterone action on fluid/electrolyte levels? Where? Stimulation? Deficiency?
Definition
-Is a mineralocorticoid which acts to retain Na+ (water too because it follows) and secrete K+ by increasing ENaC insertion into tubule cells (Epith. Na Channel)
-Secreted by zona glomerulosa of adrenal cortex
-Stimulated by angiotensin II (and low Na/high K)

-Deficiency causes diabetes insipidus
Term
What is the renin pathway and result? Where from and why? Where does a drug fit in?
Definition
-Released by justaglomerular cells in responce to low BP, blood volume, or Na

-Renin makes Angiotensinogen (A) to A-I
-A-I is made into A-II by angiotensin converting enzyme (ACE)
-A-II then causes vasoconstriction, aldosterone secretion, and renin inhibition (feedback inhibition)
-Overall, this path leads to increased blood pressure

-We can use ACE inhibitors to treat hypertension
Term
Angiotensin II action and receptor?
Definition
-Binds to Gq coupled receptor to increase PKC and lead to aldosterone secretion by zona glomerulosa of adrenal cortex
Term
Vit D's most active form and action? Enzyme needed in production?
Definition
-Calcitriol (1,25-(OH)2D)
-Stimulates dietary Ca2+ uptake, and reabsorption in the kidneys (of phosphate too)
-Also stimulates resorption from the bones of calcium and phosphate
-needs 1a-Hydroxylase (needs sunlight)
Term
PTH stimulation and action? Receptors? Excess action?
Definition
-Parathyroid hormone responds to low Ca2+ with high sensitivity (repressed by hypercalcemia)
-Made by chief cells of parathyroid
-It interacts with Gs+Gq receptors (for PTH-1 receptor) in bone and renal tubules to promote bone resorption and calcium retention (and phosphate excretion)
-Works in bone by increasing osteoclast levels (resorb bone)
-excess action can lead to osteoporosis and hypercalcemia
Term
Hypercalcemia?
Definition
-Can be caused by excess PTH (chief cell adenoma) or excess vit D
-Causes "stones, bones, and moans"; stones, fractures, & fatigue
-Will also have hypophosphatemia if it's from PTH
Term
Hypocalcemia?
Definition
-caused by PTH or Vit D def.
-Severe causes childhood rickets
-Milder caused OSTEOMALACIA later in life
Term
Vit D-dependent rickets type I?
Definition
-Caused by mutation in gene for 1a-hydroxylase (for Vit D conversion to calcitrol, aka 1,25(OH)2D)
-Low calcitrol leads to low phosphate and Ca2+ in blood from poor intestinal absorption
Term
Vit D-dependant rickets type II?
Definition
-Caused by a bad receptor for calcitrol [1,25(OH)2D]
Term
Osteomalacia?
Definition
-Adult vit D def.
Term
Receptor result for;
-Vasopressin?
-ANP
-Angiotensin II
-PTH
Definition
-PKA
-PKG
-PKC (Gq)
-PKA & PKC (Gq & Gs)
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