PHGY 312 Lecture Notes - Lecture 7: Amiloride, Bile Acid, Facilitated Diffusion
24 May 2016
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Phgy 312-lecture 7: organic solute ii and na transport i. Prototype for physiological organic anions ohippurate, camp, bile salts, antibiotics. Clearance of pah is a measure of effective renal plasma flow=upahv/ppah oamount filtered depends on pah delivery to the kidney; more flow=more pah cleared. There"s secretion across pt (s3 segment) so there"s 6 times more pah compared to that filtered. In s3, pah is extruded out of the cell into the tubule lumen in exchange for anions (apical) Entry of pah into the cell is mediated by an exchanger that exchanges dc2- for pah (basolateral) othis is energetically wasteful! Na cycles dc2- back into the cell via a symport transporter that pumps 3na+ in/dc2- going in. Basolateral uptake is by facilitated diffusion through oct1 ooct1=facilitated diffusion mechanism (driven by voltage gradient) Apical efflux is through h+/organic cation exchange (h+ into cell, cation into lumen) Amiloride gets into the lumen blocks na absorption in the cd.
