TY - JOUR
T1 - Na-K-ATPase isoform (α3, α2, α1) abundance in rat kidney estimated by competitive RT-PCR and ouabain binding
AU - Lucking, Karl
AU - Nielsen, Jesper M.
AU - Pedersen, Per Amstrup
AU - Jørgensen, Peter L.
PY - 1996/12/1
Y1 - 1996/12/1
N2 - For understand-ing the regulation of sodium reabsorption, it is important to know whether the α2- or α3-isoform of Na-K-adenosinetriphosphatase (Na-K-ATPase) is expressed in mammalian kidney in addition to the predominant a-isozyme. Here we applied competitive polymerase chain reaction (PCR) for estimation of mRNAin parenchymal zones of rat kidney for comparison to high-affinity [3H]ouabain binding. The α3-isoform mRNA was demonstrated to form 0.04-0.05% of the amount of arisoform mRNA in the cortex, medulla, and papilla of rat kidney. The α2-mRNA was demonstrated in all three zones and constituted 0.03% of the amount of arinRNA in cortex. The abundance of the a. truncated mRNA was 0.1-0.8% of that of the ai-mRNA. The upper limit for expression of Na-K-ATPase isozyme with high ouabain affinity (dissociation constant, 69-141 nM) was 0.096-0.14% of the concentration of α1β1-Na-K-ATPase. Thus a small but well-defined pool of α2- and α3-isoforms constitutes £0.1% of the amount of oti-isoform at both the mRNA and protein level in rat kidney.
AB - For understand-ing the regulation of sodium reabsorption, it is important to know whether the α2- or α3-isoform of Na-K-adenosinetriphosphatase (Na-K-ATPase) is expressed in mammalian kidney in addition to the predominant a-isozyme. Here we applied competitive polymerase chain reaction (PCR) for estimation of mRNAin parenchymal zones of rat kidney for comparison to high-affinity [3H]ouabain binding. The α3-isoform mRNA was demonstrated to form 0.04-0.05% of the amount of arisoform mRNA in the cortex, medulla, and papilla of rat kidney. The α2-mRNA was demonstrated in all three zones and constituted 0.03% of the amount of arinRNA in cortex. The abundance of the a. truncated mRNA was 0.1-0.8% of that of the ai-mRNA. The upper limit for expression of Na-K-ATPase isozyme with high ouabain affinity (dissociation constant, 69-141 nM) was 0.096-0.14% of the concentration of α1β1-Na-K-ATPase. Thus a small but well-defined pool of α2- and α3-isoforms constitutes £0.1% of the amount of oti-isoform at both the mRNA and protein level in rat kidney.
KW - Ai truncated form; messenger ribonucleic acid levels
KW - Parenchymal zones
KW - Reverse transcription-polymerase chain reaction
KW - Sodium-potassium pump
KW - Sodium-potassium-adenosinetriphosphatase
UR - http://www.scopus.com/inward/record.url?scp=0029781307&partnerID=8YFLogxK
M3 - Journal article
C2 - 8770155
AN - SCOPUS:0029781307
SN - 0002-9513
VL - 271
JO - American Journal of Physiology
JF - American Journal of Physiology
IS - 2 PART 2
ER -