[Pathogenesis of diabetic microangiopathy. Protein and basement membrane synthesis in isolated kidney glomeruli of diabetic and non-diabetic rats].
In incubation experiments with isolated glomeruli, an increased synthesis of protein and basement membranes was detected in streptozotocin-diabetic rats compared to metabolically healthy controls. Chemical analysis of isolated basement membranes and incorporation studies did not give any indication of enhanced hydroxylation of lysine in the diabetic membrane. Different glucose concentration in the incubation medium and insulin in vitro did not influence protein and basement membrane synthesis of non-diabetic glomeruli. On the other hand, in diabetic glomeruli the synthetic activity depends on glucose concentration. Insulin had a stimulatory effect on protein and basement membrane synthesis diminished at lower glucose concentration and did not inhibit the increased synthetic activity demonstrated at higher glucose concentration. Therefore, these results may be attributable to an energy deficit of incubated glomeruli and not to a lower glucose stimulation of synthesis. By treatment of diabetic rats with insulin in vivo the synthetic activity was not affected by brief normalization of blood sugar. Insulin treatment from the beginning of diabetes only lead to a normalization of protein synthesis in moderate metabolic control. On the other hand, a rise of basement membrane synthesis could only be prevented by strict metabolic control of the rats. These results show that basement membrane synthesis reacts more sensitively to the diabetic situation than overall protein synthesis. Insulin deficiency does not appear to be one of the factors directly influencing basement membrane synthesis.
D000818:Animals; D001485:Basement Membrane / Q000378:metabolism*; D001786:Blood Glucose / Q000032:analysis; D003925:Diabetic Angiopathies / Q000503:physiopathology*; D005947:Glucose / Q000378:metabolism; D006901:Hydroxylysine / Q000096:biosynthesis; D007328:Insulin / Q000494:pharmacology; D007678:Kidney Glomerulus; D008239:Lysine / Q000378:metabolism; D014176:Protein Biosynthesis; D051381:Rats
D001786:Blood Glucose; D007328:Insulin; D006901:Hydroxylysine; D005947:Glucose; D008239:Lysine
Untersuchungen zur Pathogenese der diabetischen Mikroangiopathie. Protein- und Basalmembran-Synthese in isolierten Nierenglomerula diabetischer und nicht-diabetischer Ratten.