Islet NADPH oxidase activity is modulated unevenly by different secretagogues.
NADPH oxidase expression and activity have been measured in pancreatic islets under normal conditions, but its potential modulatory role upon insulin secretion remains unclear. We have currently studied NADPH oxidase activity in islets isolated from normal rats as well as the effect of its inhibition upon insulin secretion stimulated by different secretagogues. Glucose, arginine, fatty acids and KCl increased islet NADPH oxidase activity in a stimulus-dependent manner. DPI inhibited such increase in different proportions and affected unevenly insulin secretion, namely, it decreased the effect of high glucose, increased that of oleic acid and KCl, without changing the one induced by palmitic acid. Our data provide evidence that the contribution of NADPH activity to reactive oxygen species production in normal rat islets as well as its effect upon insulin secretion is uneven and highly stimulus-dependent.
Rebolledo
Oscar R
OR
CENEXA (UNLP-CONICET LA PLATA, PAHO/WHO Collaborating Center), School of Medical Sciences, Facultad de Ciencias Médicas UNLP, Calles 60 y 120, 1900, La Plata, Argentina.
Raschia
María A
MA
Borelli
María I
MI
García
María E
ME
Gagliardino
Juan J
JJ
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005227:Fatty Acids / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D000074624:NADPH Oxidase 1; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D005227:Fatty Acids; D007328:Insulin; D008562:Membrane Glycoproteins; D011189:Potassium Chloride; D001120:Arginine; D009247:NADH, NADPH Oxidoreductases; C500593:Cybb protein, rat; D000074624:NADPH Oxidase 1; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498911:Nox4 protein, rat; D005947:Glucose