Characterization and control of proton-ATPase along the nephron.
Since it is now well established that the Na-H exchanger accounts for only part of tubular proton secretion, we attempted to characterize the molecular processes responsible for the remaining moiety. In particular, we evaluated the possible roles of proton pumps in urinary acidification. For this purpose, we characterized ATPase activities associated with the electrogenic H pump, on the one hand, and with H-K-ATPase, on the other. In order to circumvent the axial heterogeneity of nephron, this study was carried out on microdissected segments of nephron. The present report summarized experiments which aimed: (1) at characterizing H-ATPase and H-K-ATPase on kinetic and pharmacologic bases in the successive segments of mammalian nephrons; (2) at evaluating the ionic transport mediated by these two ATPases; and (3) at determining the factors which control the activity of these pumps.
Khadouri
C
C
Laboratoire de Physiologie Cellulaire, URA 219 CNRS, Collège de France, Paris, France.
Cheval
L
L
Marsy
S
S
Barlet-Bas
C
C
Doucet
A
A
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D027682:Cation Transport Proteins; D017506:H(+)-K(+)-Exchanging ATPase; D007477:Ions; D007684:Kidney Tubules / Q000201:enzymology*; D008297:Male; D009399:Nephrons / Q000201:enzymology*; D011191:Potassium Deficiency / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
D027682:Cation Transport Proteins; D007477:Ions; D000251:Adenosine Triphosphatases; C022761:potassium transporting ATPase; D017506:H(+)-K(+)-Exchanging ATPase