| pubmed-article:10188625 | pubmed:abstractText | The present study examines the acute effect of leptin (50 nM) on insulin secretion and on the fractional outflow rates of 45Ca2+ and 86Rb+ from pancreatic islets isolated from male lean albino rats. Under a constant physiological glucose concentration (5.6 mM), the addition of leptin to the perifusion medium led to an increment in 45Ca2+ fractional outflow rate followed by a significant (p < 0.05) increase (26%) in the insulin release. At low glucose concentration (2.8 mM), leptin also elicited a significant (p < 0.05; 50-60%) increase in insulin secretion. However, under supraphysiological (16.7 mM) glucose concentration, the rapid first-phase insulin secretion response was abolished. At low glucose levels, islets perifused in the presence of leptin presented a lower 86Rb+ fractional outflow rate compared with perifused controls. In contrast, when glucose was switched to 16.7 mM, compared with controls, a slight increase in the 86Rb+ fractional outflow rate was observed instead. These in vitro data provide evidence that, by changing K+ fluxes, leptin might modulate insulin secretion from pancreatic islets. | lld:pubmed |
