Rt-pcr analysis of na+/h+ exchanger mrnas in the rat medullary
thick ascending limb.
Borensztein, Pascale, Marc Froissart, Kamel Laghmani, Maurice Bichara,
and Michel Paillard.
D[acute]epartement de physiologie, Universit[acute]e Pierre et
Marie Curie, Institut National de la Sant[acute]e et de la Recherche
M[acute]edicale Unit[acute]e 356, and H[circumflex]opital Broussais,
Paris, France.
APStracts 2:0049F, 1995.
The thick ascending limb (TAL) of rat kidney absorbs bicarbonate
secondary to proton secretion, but displays both basolateral and
luminal Na+/H+ exchange (NHE) activity. Several Na+/H+ exchanger
genes, including NHE-1, NHE-2, NHE-3, and NHE-4, are expressed in the
kidney. To identify the NHE isoforms expressed in the rat medullary
TAL (MTAL), we used the reverse transcription-polymerase chain
reaction (RT-PCR) to detect the mRNAs for NHE in microdissected MTAL.
RT-PCR amplification from total RNA was performed between two
specific primers for each NHE isoform. In rat kidney homogenate, the
four NHE isoform mRNAs were detected and the identity of the PCR
products was demonstrated by the sizes of the fragments, digestion
with restriction enzymes, and Southern-blot analysis. In
microdissected rat MTAL, NHE-3 was strongly expressed and NHE-1 mRNA
was also detected, whereas NHE-2 and NHE-4 mRNAs were not detected.
Then NHE-3 could be the apical Na+/H+ exchanger and NHE-1 the
basolateral isoform in the MTAL.
Received 7 February 1995; accepted in final form 22 March 1995.
APS Manuscript Number F38-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 April 1995.