Na-K-ATPase isoform (α3, α2, α1) abundance in rat kidney estimated by competitive RT-PCR and ouabain binding
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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.
Original language | English |
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Journal | American Journal of Physiology |
Volume | 271 |
Issue number | 2 PART 2 |
ISSN | 0002-9513 |
Publication status | Published - 1 Dec 1996 |
- Ai truncated form; messenger ribonucleic acid levels, Parenchymal zones, Reverse transcription-polymerase chain reaction, Sodium-potassium pump, Sodium-potassium-adenosinetriphosphatase
Research areas
ID: 227044094