Hormone Action III Flashcards
calcitonin
- has what chemical structure?
- secreted by what cells?
- under what regulation?
- has what effects?
- has cyclical structure at C-terminal
- by parafollicular cells in the thyroid
- in response to high plasma calcium
- acts on bone & kidney to:
- lower calcium
- lower phosphate
Vitamin D3
- is found in what major form in the blood?
- is converted to its active form where?
- under what regulation?
- 25(OH)-D3 = major form in the blood (post liver)
- 25(OH)-D3 converted 1,25(OH)2-D3 aka calcitriol in the renal tubule by 1a-hydroxylase activity
- 1a-hydroxylase activity stimulated by hypocalcemia (PTH) and hypophosphatemia
the parathyroid gland and thyroid gland
- secretge what hormones?
- that have what ion effects?
- in response to blood calcium levels (high or low)?
atrial natruiretic peptide (ANP)
- secreted by what tissue?
- in response to what states?
- has what effects?
- cardiac tissue (atria)
- in response to: high BP
- inc NaCl intake
- nc ECF volume
- effects: natiuresis / diuresis / vasodilation / aldosterone excretion
what causes diabetes insipidus?
how to differentiate it from diabetes mellitus?
- diabeties insipidus = lack of ADH.
- ADH acts on DCT & collecting tubules to induce water reabsorption & without it, water gets excreted
- DI vs DM:
- DI: low urine osmolarity
- DM: glucose in urine
insulin
- produced by what cells
- is synthesized how
- binds to what kind of receptor & induces an intracellular response how?
- has what effects
- Beta cells in the pancreas
- synthesized as a prepropeptide
- cleaved twice to yield mature insulin: A chain (21 aas) + B-chain (30 aas)
- acts on tyrosine kinase receptor, trigger intracellular kinase cascade. effects:
- glucose uptake
- anabolic effects - glycogen synthesis / lipogenesis
glucagon
- produced by what ells?
- synthesized how?
- acts on what receptor & triggers and intracellular response in what way?
- has what effects?
- alpha cells in the pancreas
- synthesized as pre-propeptide
- acts on GCPR (Gs) triggering adenylate cyclase-cAMP-PKA cascade. effects:
- catabolic: lipolysis, glycogenolysis
pancreatic polypeptide?
- produed by what cells?
- has what effects?
- F-cells
- increases glycogenolysis
somatostatin
- produced by what cells?
- has what effects?
- produced by delta cells of the pancreas
- inhibits
- insulin AND glucagon secretion
- release of GH from somatrophes
the adrenal medulla produces what hormones?
from where are these hormones derived?
to what receptors do these hormones bind?
- NE and E
- NE
- derived from tyrosine
- binds to a1, a2, B1 receptors
- E
- dervied from NE by phenylethanolamine-N-methyltransferase (PNMT) under + control by glucocorticoids
- binds to a1, a2, B1 and B2
- NE
what is PMNT and what does it do?
by what is it stimulated?
converts NE to E in the adrenal medulla. stimulated by glucocorticoids from the adrenal cortex
alpha and beta receptors are what kind of receptors?
what stmulates them and how does this induce an intracellular response?
- are GCPRS
- a1, a2: muscle contraction
- a1 = Gq: PLC-IP3/DAG-Ca++ –> SM contraction
- a2 = Gi: inhibition of Gs (AC-cAMP-PKA) –> inhibition of SM relaxation –> SM contraction
- b1, b2: smooth muscle relaxation / cardiac relaxation / glycogenolysis (b2)
- B = Gs: AC-cAMP-PKA = relaxation
- a1, a2: muscle contraction
what is the role of ghrelin?
appetite stimulation
what is the role of gastrin?
stimulates HCl & pepsin secretion
what is the role of glucagon-like peptide (GLP)
- potentiates insulin secretion
- inhibits glucagon secretion
