Maintenance of pancreatic endocrine cells of neonatal rat: Part VI--Effects of medium with fructose and 2-deoxyglucose
Kagawa, S.; Wakabayashi, S.; Nakao, K.; Mimura, K.; Matsuoka, A.
Indian Journal of Biochemistry and Biophysics 22(2): 65-70
1985
ISSN/ISBN: 0301-1208 PMID: 3905584 Document Number: 258798
Pancreatic .beta.-cells of neonatal rats were maintained for 7 days in glucose-depleted TCM 199 media supplemented with either 5.5 mM fructose or 5.5 mM fructose and 0.1 mM 2-deoxyglucose, and changes in their secretory competence during culture were monitored with the use of both static incubation and perifusion techniques. Under culture conditions, with the basal medium containing 5.5 mM fructose alone, the amount of insulin released into medium, either chronically or during static incubation and perifusion period, was remarkably decreased by day 7 of culture, and islets degenerated. In contrast, supplementation with 2-deoxyglucose gradually restored the recovery of insulin released into medium, its final level was 65% of the inital level (day 0) and the insulin content was increased 2.2-fold. Moreover, after 7 days there were 5.7-, 5.2- and 2.4-fold increases in insulin secretion during a 2 h-incubation with 16.7 mM glucose, 10 mM leucine and 10 mM 2-ketoisocaproate, respectively, compared to the maximal values observed on day 0. The perifusion study demonstrated that .beta.-cells at day 0 showed a minimal first phase of insulin secretion in response to glucose and a diminished second phase in response to either leucine or 2-ketoisocaproate whereas after the 7-day culture in 2-deoxyglucose-supplemented medium, .beta.-cells demonstrated a biphasic insulin secretory pattern with glucose stimulation and also an increased second phase with leucine and 2-ketoisocaproate. Further the addition of 2-deoxyglucose allowed a selective survival of endocrine cells. This corresponded well with a remarkable reduction of culture DNA content. These findings suggest that the functional maturation of neonatal rat .beta.-cells may occur during culture with glucose-depleted medium.