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Friday, January 8, 2016

💂ATRIAL NATRIURETIC FACTOR💂



💧26 AA peptide hormone 

💧synthesised from a prohormone in atrial secretory granules released in response to atrial stretch /  wall tension 

💧plasma half life, t ½ β  ~ 3 mins 

💧maximal natriuresis is less than that seen with frusemide

💧however ANF is ~ 100 times as potent 

💧receptors are concentrated in cortical  glomeruli 

💧the postulated second messenger is cGMP ? 

💧there is no direct effect upon Na +  transport, or the Na + /K +-ATPase 

💧neither amiloride nor prostaglandin inhibitors have an effect upon its actions 

💧ANF effects include

🎯systemic vasodilatation ( mostly venodilation--> transient hypotension, decreases preload

🎯increases salt delivery to distal tubule

🎯decreases plasma renin 

🎯decreases plasma aldosterone 

🎯increases urinary excretion of Na, K, Ca, Mg, Phosphate, Chloride

🎯increases urine volume

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