Aldosterone regulation of sodium channel gamma-subunit mRNA in cortical collecting duct cells

Am J Physiol. 1996 Jul;271(1 Pt 1):C423-8. doi: 10.1152/ajpcell.1996.271.1.C423.

Abstract

Specific regulatory mechanisms of aldosterone-stimulated Na+ reabsorption through the apical amiloride-sensitive channel are unknown. In this study, we examined the effects of aldosterone on Na+ channel gamma-subunit mRNA levels in cultured rabbit cortical collecting duct cells. With the use of reverse transcriptase-polymerase chain reaction (RT-PCR) with RNA isolated from aldosterone-treated cells and degenerate primers, a 446-base pair (bp) PCR product was amplified and further characterized by nested PCR and sequencing. The nested PCR yielded a predicted 164-bp product. Sequencing of the 446-bp PCR product revealed 83% nucleotide and 91% amino acid identity to the rat colonic Na+ channel gamma-subunit. The relative abundance of Na+ channel mRNA was determined by quantitative PCR after a 24-h aldosterone treatment. The results demonstrate that Na+ channel gamma-subunit mRNA levels were significantly higher (2.6 +/- 0.42) in aldosterone-treated cultures vs. the controls. This increase, however, is less than the aldosterone-induced increase (3.2 +/- 2.0) in the amiloride-sensitive short-circuit current. These results indicate that Na+ channel gamma-subunit mRNA levels are increased by aldosterone and that this increase is likely to be responsible, at least in part, for the aldosterone-induced Na+ current in the kidney.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aldosterone / pharmacology
  • Aldosterone / physiology*
  • Androstanols / pharmacology
  • Animals
  • Base Sequence
  • Cells, Cultured
  • Electric Conductivity
  • Electrophysiology
  • Kidney Cortex
  • Kidney Tubules, Collecting / cytology
  • Kidney Tubules, Collecting / drug effects
  • Kidney Tubules, Collecting / metabolism*
  • Molecular Probes
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • RNA, Messenger / metabolism*
  • Rabbits
  • Rats
  • Sodium Channels / genetics*
  • Transcription, Genetic

Substances

  • Androstanols
  • Molecular Probes
  • RNA, Messenger
  • Sodium Channels
  • Aldosterone
  • 11,17-dihydroxy-6-methyl-17-(1-propynyl)androsta-1,4,6-triene-3-one