Influence of experimental diabetes on the kinetic behaviour of renal cortex hexose monophosphate dehydrogenases.
1. Short term (1-2 hr) and long-term (2 days) effects of experimental alloxan induced diabetes on the kinetics of the renal hexose monophosphate shunt dehydrogenases are reported. 2. Alloxan diabetes for 2 days significantly increased kidney weight (16%) adding about 80 mg/day per g of kidney. No significant changes were found in renal growth 1-2 hr after alloxan injection. 3. Under these experimental conditions, the activities of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase significantly increased (103 and 33% respectively) at all substrate concentrations, without affecting the KmS of either enzyme. 4. There was no effect of alloxan on the activity of these enzymes at 1-2 hr. Saturation curves show that all enzymes exhibited a M-M kinetic without evidence of sigmoidicity. 5. The results suggest that increased renal hexose monophosphate dehydrogenases activities are due to increased concentrations of the rate limiting proteins. 6. The relationship between these changes and renal hypertrophy is also discussed.
Peragón
J
J
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Granada, Espana.
Aranda
F
F
García-Salguero
L
L
Lupiáñez
J A
JA
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000201:enzymology* / Q000503:physiopathology; D007672:Kidney Cortex / Q000201:enzymology* / Q000254:growth & development; D007700:Kinetics; D009929:Organ Size; D010427:Pentose Phosphate Pathway; D010734:Phosphogluconate Dehydrogenase / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D002237:Carbohydrate Dehydrogenases; C020552:galactose-6-phosphate dehydrogenase; D010734:Phosphogluconate Dehydrogenase