Direct evidence for opposite effects of D-glucose and D-glyceraldehyde on cytoplasmic pH of mouse pancreatic beta-cells.
The effects of D-glucose, D-glyceraldehyde, glibenclamide, D-600, NH4+ and high concentrations of K+ on cytoplasmic pH (pHi) were investigated in dispersed and cultured pancreatic beta-cells from ob/ob mice. The cytoplasmic pH was measured with the fluorescent H+-indicator quene 1. The average pHi value in resting beta-cells was 6.71. Addition of 20 mM of the physiological stimulus D-glucose increased pHi with 0.05 units. Both glibenclamide and high concentrations of K+ decreased pHi. The latter effects were completely reversed by D-600, supporting the notion that free cytoplasmic Ca2+ can be involved in the regulation of pHi. In contrast to D-glucose, 10 mM of D-glyceraldehyde decreased pHi by 0.09 units, an effect persisting even in the presence of D-600. From the present study it is evident that D-glyceraldehyde and D-glucose have opposite effects on pHi in pancreatic beta-cells.
D000641:Ammonia / Q000494:pharmacology; D000818:Animals; D003593:Cytoplasm / Q000187:drug effects*; D005260:Female; D005711:Gallopamil / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D005905:Glyburide / Q000494:pharmacology; D005985:Glyceraldehyde / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007515:Islets of Langerhans / Q000187:drug effects*; D008297:Male; D051379:Mice; D008820:Mice, Obese; D011188:Potassium / Q000494:pharmacology
D005985:Glyceraldehyde; D005711:Gallopamil; D000641:Ammonia; D005947:Glucose; D011188:Potassium; D005905:Glyburide