Rapid oscillation of insulin release by the rat pancreatic islets under stringent Ca2+-free conditions

T Aizawa
2000 Journal of Endocrinology  
Oscillation of insulin release by the pancreatic islets was evaluated under stringent Ca 2+ -free conditions for the first time. Isolated single rat islets were exposed to 16·7 mM glucose in the presence of 1·9 mM Ca 2+ , or under the stringent Ca 2+ -free conditions (Ca 2+ omission with 1 mM EGTA, 6 µM forskolin and 100 nM phorbol 12-myristate 13-acetate). Fifteen minutes after the initiation of glucose stimulation, effluent was collected at a 6-s interval, insulin was determined in duplicate
more » ... y a highly sensitive insulin radioimmunoassay, and oscillation and pulsatility of release statistically analyzed. Significant oscillation of insulin release was observed in all islets irrespective of presence and absence of Ca 2+ . Significant pulsatility of release was detected in 7 of 11 islets in the presence of Ca 2+ and three of six islets in the absence of Ca 2+ . In conclusion, high glucose elicits oscillatory insulin release both in the presence and absence of extracellular Ca 2+ .
doi:10.1677/joe.0.1660545 pmid:10974649 fatcat:feo3qjmqyne47o46wvc2ru4t5e