ADH Flashcards
Where is ADH formed?
Supraoptic hypothalamic nucleus and stored in the posterior pituitary gland
What is vasopressin?
Another name for ADH
What kind of hormone is ADH?
A peptide hormone
What physiological factors stimulate ADH release?
Low blood pressure and high serum osmalality
What is the impact of ADH on the kidney?
Increases water re-absorption at the distal convoluted tubule + collecting duct
Increases sodium re-absorption in the ascending loop of henle
Which receptors in the hypothalamus stimulate ADH release?
Osmoreceptors detect changes in plasma osmolality (increased osmolality = stimulation)
Baroreceptors detect low BP = stimulates ADH release
Angiotensin 2 is also detected in blood indicating low blood pressure, which stimulates ADH release
Which cells do ADH stimulate in the collecting duct?
Principal cells
Which receptor does ADH bind to in the distal convoluted tubule and collecting duct?
G protein linked V2 receptor
What happens when ADH binds to receptors on the DCT and collecting duct?
G protein linked V2 receptor activated adenylate cyclase enzyme, which converts ATP to cyclic AMP, which activates protein kinase A which stimulates a series of events which results in water channels called aquaporin type 2 are inserted into the luminal side of the cell
What kind of aquaporin does ADH stimulate?
aquaporin type 2
What is the impact of ADH on plasma volume?
It increases it = increases BP
What is the impact of ADH on urine osmolality?
It increases it
What is the impact of ADH on blood vessels?
Binds to V1 receptors to increase intracellular calcium = vasoconstriction
What is the difference between V1 and V2 ADH receptors?
V2 - on distal convoluted tubule and collecting duct - stimulates water re-absorption
V1 - on blood vessels - stimulates vasoconstriction
What condition is caused by low ADH secretion?
Diabetes insipidus
