Localization of thiazide-sensitive Na(+)-Cl(-) cotransport and associated gene products in mouse DCT

Am J Physiol Renal Physiol. 2001 Dec;281(6):F1028-35. doi: 10.1152/ajprenal.0148.2001.

Abstract

The mammalian distal nephron develops a complex assembly of specialized cell types to accomplish the fine adjustment of urinary electrolyte composition. The epithelia of the distal convoluted tubule (DCT), the connecting tubule (CNT), and the cortical collecting duct (CCD) show an axial structural heterogeneity that has been functionally elucidated by the localization of proteins involved in transepithelial ion transport. We compared the distribution of the thiazide-sensitive Na(+)-Cl(-) cotransporter (TSC), basolateral Na(+)/Ca(2+) exchanger (Na/Ca), cytosolic calcium-binding proteins calbindin D(28K) and parvalbumin, and the key enzyme for selective aldosterone actions, 11 beta-hydroxysteroid-dehydrogenase 2 (11HSD2), in the distal convolutions of the mouse. In the mouse, as opposed to the rat, we found no clear subsegmentation of the DCT into a proximal (DCT1) and a distal (DCT2) portion. The TSC was expressed along the entire DCT. Na/Ca and calbindin D(28K) were similarly expressed along most of the DCT, with minor exceptions in the initial portion of the DCT. Both were also present in the CNT. Parvalbumin was found in the entire DCT, with an occasional absence from short end portions of the DCT, and was not present in CNT. 11HSD2 was predominantly located in the CNT and CCD. Short end portions of DCT only occasionally showed the 11HSD2 signal. We also observed an overlap of 11HSD2 immunoreactivity and mRNA staining. Our observations will have implications in understanding the physiological effects of gene disruption and targeting experiments in the mouse.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 11-beta-Hydroxysteroid Dehydrogenase Type 2
  • Animals
  • Calbindins
  • Carrier Proteins / analysis*
  • Carrier Proteins / immunology
  • Hydroxysteroid Dehydrogenases / genetics
  • Hydroxysteroid Dehydrogenases / immunology
  • Hydroxysteroid Dehydrogenases / metabolism
  • Immunohistochemistry
  • In Situ Hybridization
  • Kidney Tubules, Distal / chemistry*
  • Kidney Tubules, Distal / enzymology
  • Kidney Tubules, Distal / ultrastructure
  • Male
  • Mice
  • Models, Biological
  • Parvalbumins / analysis
  • Parvalbumins / immunology
  • RNA, Messenger / biosynthesis
  • Receptors, Drug / analysis*
  • Receptors, Drug / immunology
  • S100 Calcium Binding Protein G / analysis
  • S100 Calcium Binding Protein G / immunology
  • Sodium Chloride Symporters
  • Sodium-Calcium Exchanger / analysis
  • Sodium-Calcium Exchanger / immunology
  • Solute Carrier Family 12, Member 3
  • Symporters*

Substances

  • Calbindins
  • Carrier Proteins
  • Parvalbumins
  • RNA, Messenger
  • Receptors, Drug
  • S100 Calcium Binding Protein G
  • Slc12a3 protein, mouse
  • Sodium Chloride Symporters
  • Sodium-Calcium Exchanger
  • Solute Carrier Family 12, Member 3
  • Symporters
  • thiazide receptor
  • Hydroxysteroid Dehydrogenases
  • 11-beta-Hydroxysteroid Dehydrogenase Type 2