Stimulation of rat-kidney hexose monophosphate shunt dehydrogenase activity by chronic metabolic acidosis.

The effect of chronic metabolic acidosis on the kinetic behaviour of renal glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase have been investigated. Acidosis induced a significant increase in both enzyme activities at all substrate concentrations used. Saturation curves of both dehydrogenases were hyperbolic with no evidence of sigmoidicity. Maximum activities were found after 7 days of acidosis with no significant change in the Km values. The results suggest that stimulated renal hexose monophosphate dehydrogenases activities are probably due to an increased intracellular concentration of these enzymes. The relationship between these changes and those generated in the metabolic acidosis are also discussed.