Abstract

The electrofusion-derived rat insulin-secreting cell line BRIN-BD11 was cultured in five different commercially available media to determine the optimum medium for the in vitro maintenance of such clonal cell lines. Cells were cultured in RPMI-1640. DMEM, McCOY'S, F-12K, or MEM culture medium supplemented with 10% (v/v) fetal bovine serum and antibiotics (100 U/ml penicillin and 0.1 g/L streptomycin). Insulin secretion studies performed after 10 days revealed RPMI-1640 to be the best performing medium in terms of insulin secretory responsiveness to a range of stimuli including glucose, L-alanine, L-arginine, carbachol, and glibenclamide. Insulin release was significantly decreased (p < 0.01 to p < 0.05) in all other media compared to RPMI-16-10. Only the cells cultured in RPMI-1640 and DMEM showed a significant glucose-induced insulin secretory response (p < 0.01 and p < 0.05). McCOY'S gave the next best result followed by F-12K and MEM. After the 10-day culture period, the highest insulin content was found in cells cultured in RPMI-1640 and DMEM with significantly lower levels of insulin in cells cultured in McCOY'S, F-12K, and MEM (p < 0.01 to p < 0.001). RPMI-1640 was used for further studies to investigate the effects of 5.6-16.7 mmol/L glucose in culture on the secretory responsiveness of BRIN-BD11 cells. Significant responses to a number of nonglucidic secretagogues were seen following culture at 5.6 and 16.7 mmol/L glucose, although responsiveness was less than after culture with 11.1 mmol/L glucose. At 16.7 mmol/L glucose culture, glucose-stimulated insulin release was abolished.