Regulatory Mechanisms of Na+/glucose Transporters in Renal Proximal Tubule Cells

Abstract

Glucose is a key fuel and an important metabolic substrate in ammals. A number of mechanisms contribute to the changes in cellular functions that occur in response to exposure of endogenous factors. These include increased cytokines and growth factors as well as the glucose specific effects due to increased intracellular level of glucose. The kidneys play a major role in the regulation of plasma glucose levels, and ever increasing attention is now being given to renal glucose transporters as the implications including diabetes mellitus. The primary rabbit renal proximal tubule cells (PTCs) culture system utilized in my study has well recognized to retain in vitro the differentiated phenotype typical of the renal proximal tubule, including a polarized morphology and distinctive proximal tubule transport. Thus, I examined the effects of several actors on Na＋/glucose cotransporters in PTCs. ANG II, EGF, epinephrine, TCDD, high glucose, bee venom, partially inhibited [14C]-α-methyl-D-glucopyranoside (α-MG) uptake, whereas BSA stimulates α-MG uptake in PTCs. On the other hand, caffeic acid, ginsenosides, and estrogens protected oxidative stress-induced inhibition of α-MG uptake.