Abstract
The effects of tolbutamide and glibenclamide on the metabolism of cyclic AMP were investigated in pancreatic islets of the rat. Changes in cyclic AMP were assessed by measuring [3H]cyclic AMP after labeling of the islets with [2-3H]adenine. In the presence of a nonstimulatory concentration of glucose (3.3 mM), both sulfonylureas caused a rapid increase in islet [3H]cyclic AMP, which declined within 5 (tolbutamide) or 10 min (glibenclamide). In the absence of glucose, the glibenclamide effect was shortened, but the initial (1 min) response of [3H]-cyclic AMP was unaffected. Glucose could be substituted with d-glyceraldehyde but not pyruvate for prolongation of the glibenclamide response. The effect of glucose withdrawal on the glibenclamide response was reproduced by the addition of d-mannoheptulose to glucose containing media.
The [3H]cyclic AMP response to glibenclamide was influenced by prior exposure of the islets to glucose, a 30-min preincubation with 27.7 mM glucose, enhancing the response to the sulfonylurea over a subsequent 5-min stimulation period.
Sulfonylureas exerted their effects at low but not at high glucose concentrations, i.e., shifted the glucose dose-response curve to the left both for [3H]cyclic AMP accumulation and insulin release. On the other hand, increasing concentrations of the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine, progressively augmented the effects of the drugs.
Omission of Ca++ from the incubation media inhibited both the glucose and the sulfonylurea [3H]-cyclic AMP and insulin responses. Epinephrine (1 μM) partially inhibited the [3H]cyclic AMP response to both glucose and sulfonylurea, whereas insulin release was completely abolished.
It is concluded that the sulfonylurea effects on islet cyclic AMP are intimately related to those of glucose. It is suggested that sulfonylureas exert a major part of their action by facilitating the effect of glucose on the beta-cell adenylate cyclase; the increased cyclic AMP level, in its turn, enhances the secretion rate of insulin.
Full text
PDF








Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Ariëns E. J. [Oral antidiabetics. Dose, plasma concentration and effect]. Acta Diabetol Lat. 1969 Sep;6 (Suppl 1):143–176. [PubMed] [Google Scholar]
- Ashcroft S. J.H., Randle P. J., Täljedal I. -B. Cyclic nucleotide phosphodiesterase activity in normal mouse pancreatic islets. FEBS Lett. 1972 Feb 15;20(3):263–266. doi: 10.1016/0014-5793(72)80082-6. [DOI] [PubMed] [Google Scholar]
- Bowen V., Lazaus N. R. Glucose-mediated insulin release: 3',5' cAMP phosphodiesterase. Diabetes. 1973 Oct;22(10):738–743. doi: 10.2337/diab.22.10.738. [DOI] [PubMed] [Google Scholar]
- Capito K., Hedeskov C. J. Effects of glucose, glucose metabolites and calcium ions on adenylate cyclase activity in homogenates of mouse pancreatic islets. Biochem J. 1977 Mar 15;162(3):569–573. doi: 10.1042/bj1620569. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Charles M. A., Lawecki J., Steiner A. L., Grodsky G. M. Cyclic nucleotides in pancreatic islets. Tolbutamide- and arginine-induced insulin release. Diabetes. 1976 Apr;25(4):256–259. doi: 10.2337/diab.25.4.256. [DOI] [PubMed] [Google Scholar]
- Exton J. H., Lewis S. B., Ho R. J., Robison G. A., Park C. R. The role of cyclic AMP in the interaction of glucagon and insulin in the control of liver metabolism. Ann N Y Acad Sci. 1971 Dec 30;185:85–100. doi: 10.1111/j.1749-6632.1971.tb45239.x. [DOI] [PubMed] [Google Scholar]
- Gerich J. E., Charles M. A., Grodsky G. M. Regulation of pancreatic insulin and glucagon secretion. Annu Rev Physiol. 1976;38:353–388. doi: 10.1146/annurev.ph.38.030176.002033. [DOI] [PubMed] [Google Scholar]
- Grill V., Borglund E., Cerasi E. Evidence for uniform labeling of precursor and product with [3H]adenine. Biochim Biophys Acta. 1977 Sep 29;499(2):251–258. doi: 10.1016/0304-4165(77)90007-1. [DOI] [PubMed] [Google Scholar]
- Grill V., Cerasi E. Cyclic AMP metabolism and insulin release in pancreatic islets of the rat. Effects of agents which alter microtubular function. Biochim Biophys Acta. 1977 Dec 22;500(2):385–394. doi: 10.1016/0304-4165(77)90029-0. [DOI] [PubMed] [Google Scholar]
- Grill V., Cerasi E. Effect of hexoses and mannoheptulose on cyclic AMP accumulation and insulin secretion in rat pancreatic islets. Biochim Biophys Acta. 1976 Jun 23;437(1):36–50. doi: 10.1016/0304-4165(76)90345-7. [DOI] [PubMed] [Google Scholar]
- Grill V., Cerasi E. Stimulation by D-glucose of cyclic adenosine 3':5'-monophosphate accumulation and insulin release in isolated pancreatic islets of the rat. J Biol Chem. 1974 Jul 10;249(13):4196–4201. [PubMed] [Google Scholar]
- Hellman B., Idahl L. A., Danielsson A. Adenosine triphosphate levels of mammalian pancreatic B cells after stimulation with glucose and hypoglycemic sulfonylureas. Diabetes. 1969 Aug;18(8):509–516. doi: 10.2337/diab.18.8.509. [DOI] [PubMed] [Google Scholar]
- Hellman B., Idahl L. A., Lernmark A., Täljedal I. B. The pancreatic beta-cell recognition of insulin secretagogues: does cyclic AMP mediate the effect of glucose? Proc Natl Acad Sci U S A. 1974 Sep;71(9):3405–3409. doi: 10.1073/pnas.71.9.3405. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hellman B., Sehlin J., Täljedal I. B. The pancreatic -cell recognition of insulin secretagogues. IV. Islet uptake of sulfonylureas. Diabetologia. 1973 Jun;9(3):210–216. doi: 10.1007/BF01219785. [DOI] [PubMed] [Google Scholar]
- Hellman B., Sehlin J., Töljedal I. B. The pancreatic -cell recognition of insulin secretagogues. II. Site of action of tolbutamide. Biochem Biophys Res Commun. 1971 Dec 17;45(6):1384–1388. doi: 10.1016/0006-291x(71)90174-4. [DOI] [PubMed] [Google Scholar]
- Herbert V., Lau K. S., Gottlieb C. W., Bleicher S. J. Coated charcoal immunoassay of insulin. J Clin Endocrinol Metab. 1965 Oct;25(10):1375–1384. doi: 10.1210/jcem-25-10-1375. [DOI] [PubMed] [Google Scholar]
- Krishna G., Weiss B., Brodie B. B. A simple, sensitive method for the assay of adenyl cyclase. J Pharmacol Exp Ther. 1968 Oct;163(2):379–385. [PubMed] [Google Scholar]
- Kuo W. N., Hodgins D. S., Kuo J. F. Adenylate cyclase in islets of Langerhans. Isolation of islets and regulation of adenylate cyclase activity by various hormones and agents. J Biol Chem. 1973 Apr 25;248(8):2705–2711. [PubMed] [Google Scholar]
- Lacy P. E., Kostianovsky M. Method for the isolation of intact islets of Langerhans from the rat pancreas. Diabetes. 1967 Jan;16(1):35–39. doi: 10.2337/diab.16.1.35. [DOI] [PubMed] [Google Scholar]
- Loubatières-Mariani M. M., Loubatières A. L., Chapal J. Analysis of the stimulating action of tolbutamide on the secretion of insulin using mannoheptulose and diazoxide. Diabetologia. 1973 Apr;9(2):152–157. doi: 10.1007/BF01230696. [DOI] [PubMed] [Google Scholar]
- Meissner H. P., Atwater I. J. The kinetics of electrical activity of beta cells in response to a "square wave" stimulation with glucose or glibenclamide. Horm Metab Res. 1976 Jan;8(1):11–16. doi: 10.1055/s-0028-1093685. [DOI] [PubMed] [Google Scholar]
- Sams D. J., Montague W. The role of adenosine 3':5'-cyclic monophosphate in the regulation of insulin release. Properties of islet-cell adenosine 3':5'-cyclic monophosphate phosphodiesterase. Biochem J. 1972 Oct;129(4):945–952. doi: 10.1042/bj1290945. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Widström A., Cerasi E. On the action of tolbutamide in normal man. II. Modulation of glucose-induced insulin release by tolbutamide. Acta Endocrinol (Copenh) 1973 Mar;72(3):519–531. doi: 10.1530/acta.0.0720519. [DOI] [PubMed] [Google Scholar]
