Abundance of [alpha]3, [alpha]2, [alpha]1 isoforms of na,k-atpase
in rat kidney as estimated by competitive rt-pcr and ouabain
binding.
L[umlaut]ucking, Karl, Jesper M. Nielsen, Per Amstrup Pedersen, and
Peter L. J[stod]orgensen.
Biomembrane Research Centre, August Krogh Institute,
Universitetsparken 13, Copenhagen University, 2100 Copenhagen OE,
Denmark, Tel. (45) 35 32 16 78 Fax (45) 35 32 15 67
APStracts 3:0030F, 1996.
For understanding the regulation of sodium reabsorption it is
important to know if the [alpha]2 or [alpha]3 isoforms of Na,K-ATPase
are expressed in mammalian kidney in addition to the predominant
[alpha]1[beta]1-isozyme. Here we applied competitive PCR for
estimation of mRNA in parenchymal zones of rat kidney for comparison
to high affinity [3H]-ouabain binding. The [alpha]3 isoform mRNA was
demonstrated to form 0.04-0.05 % of the amount of [alpha]1 isoform
mRNA in the cortex, medulla and papilla of rat kidney. The [alpha]2
mRNA was demonstrated in all three zones and constituted 0.03% of the
amount of [alpha]1 mRNA in cortex. The abundance of the [alpha]1
-truncated mRNA was 0.1-0.8% of that of the [alpha]1 mRNA. The upper
limit for expression of Na,K-ATPase isozyme with high ouabain
affinity (KD 69-141 nM) was 0.096-0.14 % of the concentration of
[alpha]1[beta]1 Na,K-ATPase. Thus, a small but well defined pool of
[alpha]2 and [alpha]3 isoforms constitutes
Received 14 December 1995; accepted in final form 9 February
1996.
APS Manuscript Number F416-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 24 February 96