Maintenance of neonatal rat B cells in glucose-depleted medium: a perifusion study

Two groups of monolayer cultures of pancreatic cells from the neonatal rat were maintained in glucose-depleted TCM 199 medium, supplemented with 5.5 mmol galactose/l, with or without 0.1 mmol 2-deoxyglucose/l. Another group was kept in medium with 5.5 mmol galactose/l alone, following exposure for 2 days to a medium with 5.5 mmol galactose/l and 10 mumol iodoacetic acid/l to kill fibroblasts selectively. Each of these monolayers was cultured in a perifusion system for a total of 7 days so that phasic insulin secretion could be compared. On day 0, B cells responded in a monophasic fashion to acute challenge with 16.7 mmol glucose/l whereas, in the presence of 10 mumol forskolin/l and 1 mmol 3-isobutyl-1-methyl-xanthine/l, the same dose of glucose stimulated a biphasic response of approximately the same magnitude. At a concentration of 10 mmol/l, leucine and 2-ketoisocaproate both produced only minimal increase in the second phase of secretion above the basal level. No response to secretagogues was seen under culture conditions without 2-deoxyglucose. In contrast, addition of 2-deoxyglucose to the galactose-supplemented medium stimulated B cells to secrete insulin in a biphasic fashion in response to a single dose of glucose, and the stimulatory effects of leucine and 2-ketoisocaproate were also remarkably increased. Moreover, when exposed to a linear concentration gradient of glucose, leucine or 2-ketoisocaproate, these B cells responded to secretagogues in a dose-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)