Adaptation to metabolic acidosis and its recovery are associated with changes in anion exchanger distribution and expression in the cortical collecting duct.
It is well known that acid/base disturbances modulate proton/bicarbonate transport in the cortical collecting duct. To study the adaptation further we measured the effect of three days of acidosis followed by the rapid recovery from this acidosis on the number and type of intercalated cells in the rabbit cortical collecting duct. Immunofluorescence was used to determine the expression of apical pendrin in β-intercalated cells and the basolateral anion exchanger (AE1) in α-intercalated cells. Acidosis resulted in decreased bicarbonate and increased proton secretion, which correlated with reduced pendrin expression and the number of pendrin-positive cells, as well as decreased pendrin mRNA and protein abundance in this nephron segment. There was a concomitant increase of basolateral AE1 and α-cell number. Intercalated cell proliferation did not seem to play a role in the adaptation to acidosis. Alkali loading for 6-20 h after acidosis doubled the bicarbonate secretory flux and reduced proton secretion. Pendrin and AE1 expression patterns returned to control levels, demonstrating that adaptive changes by intercalated cells are rapidly reversible. Thus, regulation of intercalated cell anion exchanger expression and distribution plays a key role in adaptation of the cortical collecting duct to perturbations of acid/base.
Purkerson
Jeffrey M
JM
Department of Pediatrics, University of Rochester Medical Center, Rochester, New York, USA.
Tsuruoka
Shuichi
S
Suter
D Zachary
DZ
Nakamori
Aya
A
Schwartz
George J
GJ
D000136:Acid-Base Equilibrium / Q000502:physiology; D000138:Acidosis / Q000503:physiopathology*; D000222:Adaptation, Physiological / Q000502:physiology*; D000471:Alkalosis / Q000139:chemically induced / Q000503:physiopathology*; D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000502:physiology; D027321:Anion Transport Proteins / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D007685:Kidney Tubules, Collecting / Q000473:pathology / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000502:physiology; D006180:Proton-Translocating ATPases / Q000502:physiology; D011817:Rabbits; D017693:Sodium Bicarbonate / Q000008:administration & dosage
D001457:Anion Exchange Protein 1, Erythrocyte; D027321:Anion Transport Proteins; D026901:Membrane Transport Proteins; D017693:Sodium Bicarbonate; D006180:Proton-Translocating ATPases