Abstract: Abstract: Objective: To explore the dose- and glucose-dependency of L-alanine induced insulin secretion from INS-1E cells. Materials and Methods: Passage INS-1E cells incubated in the RPMI 1640 for 2 days, then the cells were incubated in the Krebs-Ringer buffer(KRB) with 0.1%BSA for 30 minutes. After preincubation, the cells were incubated for 60 minutes in the modified KRB containing glucose and alanine according to the protocol. After the incubation the medium was collected for insulin assay. Results: Alanine at concentration of 0.1-20mM potentiated the glucose (16.7mM) induced insulin secretion in a concentration dependent manner with a maximal effect obtained at 20mM. Glucose at concentration of 1.1mM--25mM enhanced insulin secretion in a concentration dependent manner with a maximal effect obtained at 25mM. 10mM L-alanine with 1.1mM—3.3mM glucose did not enhance insulin secretion; 10mM L-alanine with 6.7mM--25mM glucose enhanced insulin secretion in a glucose concentration dependent manner and the maximal effect obtained at 10mM L-alanine plus 25mM glucose. Conclusion: The present study shows that L-alanine can enhance glucose-induced insulin secretion of INS-1E cells, The higher glucose, the more insulin secreted.

Key words: L-alanine, beta-cell, Insulin release