Abstract
The purpose of the present study was to determine whether the renal inner medulla expresses mRNA for the rat epithelial Na+ channel (rENaC) and, if so, to define its regulatory properties using a low-Na+ diet model. We detected α, β and γ subunit mRNA in rat renal inner medulla using reverse transcriptase-polymerase chain reaction (RT-PCR) with primers specific for rENaC α, β and γ subunits. Moreover, we have developed a specific probe for the α subunit using RT-PCR with rENaC α-subunit-specific primers. The resulting cDNA was verified by sequencing and was then used in Northern blot analysis of distal colon, whole kidney and inner medulla. The probe for the rENaC α subunit hybridized not only to distal colon RNA but also to inner medulla RNA derived from rats fed a normal diet. Furthermore, we examined the effect of a low-Na+ diet on α, β and γ subunit mRNA expression of rENaC using full-length cDNA as a probe. A marked elevation of rENaC α subunit mRNA abundance in the inner medulla was observed in response to a high plasma aldosterone concentration induced by dietary Na+ deprivation. On the other hand, neither β nor γ subunit mRNA expression was enhanced by a low-Na+ diet. From these results, it is suggested that rENaC is responsible for Na+ transport in the renal inner medulla and that is probably regulated via transcriptional control of the α subunit of ENaC.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 2 April 1997 / Received after revision: 17 June 1997 / Accepted: 18 June 1997
Rights and permissions
About this article
Cite this article
Ono, S., Kusano, E., Muto, S. et al. A low-Na+ diet enhances expression of mRNA for epithelial Na+ channel in rat renal inner medulla. Pflügers Arch 434, 756–763 (1997). https://doi.org/10.1007/s004240050462
Issue Date:
DOI: https://doi.org/10.1007/s004240050462