Protein kinase C is activated in glomeruli from streptozotocin diabetic rats. Possible mediation by glucose.
AUTOR(ES)
Craven, P A
RESUMO
Glomerular inositol content and the turnover of polyphosphoinositides was reduced by 58% in 1-2 wk streptozotocin diabetic rats. Addition of inositol to the incubation medium increased polyphosphoinositide turnover in glomeruli from diabetic rats to control values. Despite the reduction in inositol content and polyphosphoinositide turnover, protein kinase C was activated in glomeruli from diabetic rats, as assessed by an increase in the percentage of enzyme activity associated with the particulate cell fraction. Total protein kinase C activity was not different between glomeruli from control and diabetic rats. Treatment of diabetic rats with insulin to achieve near euglycemia prevented the increase in particulate protein kinase C. Moreover, incubation of glomeruli from control rats with glucose (100-1,000 mg/dl) resulted in a progressive increase in labeled diacylglycerol production and in the percentage of protein kinase C activity which was associated with the particulate fraction. These results support a role for hyperglycemia per se in the enhanced state of activation of protein kinase C seen in glomeruli from diabetic rats. Glucose did not appear to increase diacylglycerol by stimulating inositol phospholipid hydrolysis in glomeruli. Other pathways for diacylglycerol production, including de novo synthesis and phospholipase C mediated hydrolysis of phosphatidylcholine or phosphatidyl-inositol-glycan are not excluded.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=303875Documentos Relacionados
- Mediation of Endogenous β-endorphin by Tetrandrine to Lower Plasma Glucose in Streptozotocin-induced Diabetic Rats
- Amino acid uptake by dorsal root ganglia from streptozotocin-diabetic rats.
- Impaired nitric oxide-dependent cyclic guanosine monophosphate generation in glomeruli from diabetic rats. Evidence for protein kinase C-mediated suppression of the cholinergic response.
- Decreased binding of epidermal growth factor in placentas from streptozotocin-diabetic rats.
- Decreased axonal transport of structural proteins in streptozotocin diabetic rats.