Long-term effects of a high glucose concentration in vitro on the oxidative metabolism and insulin production of isolated rat pancreatic islets

Metabolism. 1991 May;40(5):513-8. doi: 10.1016/0026-0495(91)90233-m.

Abstract

The present study was performed to clarify whether exposure in tissue culture of pancreatic islet B cells to high glucose concentrations will lead to glucose insensitivity and/or toxicity. For this purpose, isolated rat islets were maintained in tissue culture for up to 7 days in the presence of either 5.6, 11, or 56 mmol/L glucose and subsequently analyzed with regard to oxidative metabolism, insulin release, islet content of insulin, and insulin mRNA. Islets maintained at 56 mmol/L glucose showed a decreased insulin content, but no changes in insulin mRNA content when compared with control islets (cultured at 11 mmol/L glucose). In short-term incubations of the high-glucose cultured islets, the rate of insulin release at 1.67 mmol/L glucose was enhanced and could not be further stimulated by a 16.7-mmol/L glucose challenge. However, the insulin release at 16.7 mmol/L was decreased when compared with islets cultured at 11 mmol/L glucose. Islets cultured at 56 mmol/L glucose showed an increased oxygen uptake when incubated at 1.67 mmol/L glucose with no further stimulation at 16.7 mmol/L glucose. These islets also showed increased rates of glucose oxidation at incubation with 1.67 mmol/L glucose, but similar rates of oxidation at 16.7 mmol/L glucose as compared with islets cultured in 11 mmol/L glucose. Islets cultured at 5.6 mmol/L glucose showed decreased insulin release when incubated at either 1.67 mmol/L or 16.7 mmol/L glucose. The rates of glucose oxidation of these islets were also decreased at 16.7 mmol/L glucose when compared with the controls, whereas the oxygen uptake was decreased only during incubation at 1.67 mmol/L glucose. There was also a decreased content of insulin mRNA in these islets.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Culture Techniques
  • Glucose / metabolism*
  • Glucose / pharmacology
  • Insulin / genetics
  • Insulin / metabolism*
  • Islets of Langerhans / metabolism*
  • Male
  • Osmolar Concentration
  • Oxidation-Reduction
  • RNA, Messenger / metabolism
  • Rats
  • Time Factors

Substances

  • Insulin
  • RNA, Messenger
  • Glucose