scholarly journals Effects of glucose on the ultrastructure and insulin biosynthesis of isolated mouse pancreatic islets maintained in tissue culture

Diabetologia ◽  
1974 ◽  
Vol 10 (6) ◽  
pp. 743-753 ◽  
Author(s):  
A. Andersson ◽  
J. Westman ◽  
C. Hellerstr�m
1974 ◽  
Vol 140 (3) ◽  
pp. 377-382 ◽  
Author(s):  
Arne Andersson

Rates of glucose oxidation and insulin release in response to a wide range of glucose concentrations were studied in short-term experiments in isolated mouse pancreatic islets maintained in tissue culture for 6 days at either a physiological glucose concentration (6.7mm) or at a high glucose concentration (28mm). The curves relating glucose oxidation or insulin release to the extracellular glucose concentration obtained with islets cultured in 6.7mm-glucose displayed a sigmoid shape similar to that observed for freshly isolated non-cultured islets. By contrast islets that had been cultured in 28mm-glucose showed a linear relationship between the rate of glucose oxidation and the extracellular glucose concentration up to about 8mm-glucose. The maximal oxidative rate was twice that of the non-cultured islets and the glucose concentration associated with the half-maximal rate considerably decreased. In islets cultured at 28mm-glucose there was only a small increase in the insulin release in response to glucose, probably due to a depletion of stored insulin in those B cells that had been cultured in a high-glucose medium. It is concluded that exposure of B cells for 6 days to a glucose concentration comparable with that found in diabetic individuals causes adaptive metabolic alterations rather than degeneration of these cells.


1978 ◽  
Vol 176 (2) ◽  
pp. 619-621 ◽  
Author(s):  
A Andersson

To test further the hypothesis that ribonucleosides stimulate insulin secretion and biosynthesis by producing metabolic signals, the effects of starvation on adenosine-stimulated insulin production and the oxidation of adenosine by isolated mouse pancreatic islets were examined. No direct correlation was found between the metabolic flux and insulin secretion, since the starvation-induced impairment of the adenosine-stimulated insulin secretion was accompanied by an increased rate of adenosine oxidation. Adenosine-stimulated insulin biosynthesis was, however, unaffected by starvation.


1981 ◽  
Vol 96 (4) ◽  
pp. 498-504 ◽  
Author(s):  
J. Brunstedt ◽  
J. Høiriis Nielsen

Abstract. The effects of glucocorticoids on the pancreatic endocrine function was studied in isolated mouse pancreatic islets maintained in tissue culture for 1 to 3 weeks. Following culture for 1 week without corticoid supplement acute experiments with hydrocortisone showed no significant effect on the glucose-induced insulin release at 10−8 to 10−5 mol/l hydrocortisone. When, however, the islets were cultured in the presence of hvdrocortisone, there was an increased insulin release to the medium in a dose-dependent manner, with the maximal effect at 10−7 mol/l hydrocortisone. The release of glucagon to the medium was not affected to the same degree, but showed a slight inhibition at increasing concentrations of hydrocortisone. Short-term experiments after the culture period showed that islets cultured for 3 weeks in the presence of 10−7 to 10−5 mol/l hydrocortisone had an enhanced insulin secretion in response to glucose. The islets did not show any statistically significant change in their insulin- and DNA-content after 3 weeks of culture with hydrocortisone, but a marked reduction in the content of glucagon was found with increasing concentrations of hydrocortisone. The present results suggest that physiological concentrations of hydrocortisone are of importance for mouse islets to maintain their insulin production in tissue culture.


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