Fig. 4.
IL-1β generates elevations in nitric oxide production and decreases in oxygen consumption. A–D: 832/13 cells were cotreated with 1 ng/ml IL-1β and 1 mM NG-monomethyl-l-arginine (l-NMMA) for 18 h. A: nitrite was measured in the culture media using the Griess method. B and C: nitric oxide was measured by EPR spectroscopy combined with (MGD)2Fe2+ spin trapping. D: insulin secretion was measured in response to basal (2 mM) or stimulatory (16 mM) glucose concentrations. E: 832/13 cells were NT or exposed to 1 ng/ml IL-1β for 18 h. Glucose-stimulated insulin secretion was measured in response to basal (2 mM) or stimulatory (16 mM) glucose concentrations in the presence or absence of 10 μM dimethylmalate (DMM), with DMM added only during the final 2 h of the secretion experiment. Data are presented as means ± SE of 3 independent experiments. ***P < 0.001; **P < 0.01; *P < 0.05.