Regulation of renal tubular glucose reabsorption by Akt2/PKBβ

Am J Physiol Renal Physiol. 2010 May;298(5):F1113-7. doi: 10.1152/ajprenal.00592.2009. Epub 2010 Feb 17.

Abstract

Akt/PKB is known to regulate the facilitative glucose carrier GLUT4. Nothing is known, however, of the role of Akt/PKB in the regulation of renal epithelial transport. To explore whether Akt2/PKBβ influences the Na(+)-coupled glucose cotransporter SGLT1, human SGLT1 was expressed in Xenopus laevis oocytes with or without Akt/PKB, and electrogenic glucose transport was determined by dual-electrode voltage clamp. The coexpression of Akt/PKB in SGLT1-expressing oocytes was followed by an increase in glucose-induced currents. To study the functional significance of Akt/PKB-sensitive renal glucose transport, further experiments were performed in gene-targeted mice lacking functional Akt2/PKBβ (akt2(-/-)) and in their wild-type littermates (akt2(+/+)). Plasma glucose concentration was significantly higher in akt2(-/-) mice than in akt2(+/+) mice but was virtually identical to the plasma glucose concentration in fructose-treated akt2(+/+) mice. Urinary glucose excretion was significantly higher in akt2(-/-) mice compared with akt2(+/+) mice with or without fructose treatment. Moreover, the glucose-induced depolarization of proximal tubular cells was significantly smaller in isolated, perfused renal tubules from akt2(-/-) mice than in those from akt2(+/+) mice. In conclusion, Akt2/PKBβ plays a role in the regulation of renal glucose transport.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Animals
  • Female
  • Glucose / metabolism*
  • Humans
  • Kidney Tubules, Proximal / metabolism*
  • Mice
  • Mice, Knockout
  • Models, Animal
  • Oocytes / cytology
  • Oocytes / metabolism
  • Patch-Clamp Techniques
  • Proto-Oncogene Proteins c-akt / deficiency
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Sodium-Glucose Transporter 1 / metabolism*
  • Xenopus laevis

Substances

  • SLC5A1 protein, human
  • Slc5a1 protein, mouse
  • Sodium-Glucose Transporter 1
  • Proto-Oncogene Proteins c-akt
  • Glucose