Abstract
1. Insulin secretion was studied in isolated islets of Langerhans obtained by collagenase digestion of rat pancreas. In addition to responding to glucose and mannose as do whole pancreas and pancreas slices in vitro, isolated rat islets also secrete insulin in response to xylitol, ribitol and ribose, but not to sorbitol, mannitol, arabitol, xylose or arabinose. 2. Xylitol and ribitol readily reduce NAD+ when added to a preparation of ultrasonically treated islets. 3. Adrenaline (1μm) inhibits the effects of glucose and xylitol on insulin release. Mannoheptulose and 2-deoxy-glucose, however, inhibit the response to glucose but not that to xylitol. 4. The intracellular concentration of glucose 6-phosphate is increased when islets are incubated with glucose but not with xylitol, suggesting that xylitol does not promote insulin release by conversion into glucose 6-phosphate. 5. Theophylline (5mm) potentiates the effect of 20mm-glucose on insulin release from isolated rat islets of Langerhans, but has no effect on xylitol-mediated release. These results indicate that xylitol does not stimulate insulin release by alterations in the intracellular concentrations of cyclic AMP. 6. A possible role for the metabolism of hexoses via the pentose phosphate pathway in the stimulation of insulin release is discussed.
Full text
PDF![333](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac12/1186827/0b4ff8367c10/biochemj00718-0014.png)
![334](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac12/1186827/59c49e60ae3a/biochemj00718-0015.png)
![335](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac12/1186827/55924dc044eb/biochemj00718-0016.png)
![336](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac12/1186827/541ae534c430/biochemj00718-0017.png)
![337](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac12/1186827/ee0cf04b7d2d/biochemj00718-0018.png)
![338](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac12/1186827/672a56b285e6/biochemj00718-0019.png)
![339](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac12/1186827/dbd226c7d5f8/biochemj00718-0020.png)
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BUTCHER R. W., SUTHERLAND E. W. Adenosine 3',5'-phosphate in biological materials. I. Purification and properties of cyclic 3',5'-nucleotide phosphodiesterase and use of this enzyme to characterize adenosine 3',5'-phosphate in human urine. J Biol Chem. 1962 Apr;237:1244–1250. [PubMed] [Google Scholar]
- Brolin S. E., Berne C. The enzymatic activities of the initial glycolytic steps in pancreatic islets and acini. Metabolism. 1967 Nov;16(11):1024–1028. doi: 10.1016/0026-0495(67)90096-0. [DOI] [PubMed] [Google Scholar]
- Coore H. G., Randle P. J. Regulation of insulin secretion studied with pieces of rabbit pancreas incubated in vitro. Biochem J. 1964 Oct;93(1):66–78. doi: 10.1042/bj0930066. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HALES C. N., RANDLE P. J. Immunoassay of insulin with insulin-antibody precipitate. Biochem J. 1963 Jul;88:137–146. doi: 10.1042/bj0880137. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HOLLMANN S., TOUSTER O. The L-xylulose-xylitol enzyme and other polyol dehydrogenases of guinea pig liver mitochondria. J Biol Chem. 1957 Mar;225(1):87–102. [PubMed] [Google Scholar]
- HORECKER B. L., GIBBS M., KLENOW H., SMYRNIOTIS P. Z. The mechanism of pentose phosphate conversion to hexose monophosphate. I. With a liver enzyme preparation. J Biol Chem. 1954 Mar;207(1):393–403. [PubMed] [Google Scholar]
- Hirata Y., Fujisawa M., Sato H., Asano T., Katsuki S. Blood glucose and plasma insulin responses to xylitol administrated intravenously in dogs. Biochem Biophys Res Commun. 1966 Aug 12;24(3):471–475. doi: 10.1016/0006-291x(66)90185-9. [DOI] [PubMed] [Google Scholar]
- Howell S. L., Taylor K. W. Potassium ions and the secretion of insulin by islets of Langerhans incubated in vitro. Biochem J. 1968 Jun;108(1):17–24. doi: 10.1042/bj1080017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Krebs H. A., Notton B. M., Hems R. Gluconeogenesis in mouse-liver slices. Biochem J. 1966 Dec;101(3):607–617. doi: 10.1042/bj1010607. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kuzuya T., Kanazawa Y., Kosaka K. Plasma insulin response to intravenously administered xylitol in dogs. Metabolism. 1966 Dec;15(12):1149–1152. doi: 10.1016/0026-0495(66)90105-3. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., PASSONNEAU J. V., HASSELBERGER F. X., SCHULZ D. W. EFFECT OF ISCHEMIA ON KNOWN SUBSTRATES AND COFACTORS OF THE GLYCOLYTIC PATHWAY IN BRAIN. J Biol Chem. 1964 Jan;239:18–30. [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]
- Malaisse W. J., Malaisse-Lagae F., Mayhew D. A possible role for the adenylcyclase system in insulin secretion. J Clin Invest. 1967 Nov;46(11):1724–1734. doi: 10.1172/JCI105663. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McCORKINDALE J., EDSON N. L. Polyol dehydrogenases. I. The specificity of rat-liver polyol dehydrogenase. Biochem J. 1954 Jul;57(3):518–523. doi: 10.1042/bj0570518. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Montague W., Howell S. L., Taylor K. W. Pentitols and the mechanism of insulin release. Nature. 1967 Sep 2;215(5105):1088–1089. doi: 10.1038/2151088a0. [DOI] [PubMed] [Google Scholar]
- Montague W., Taylor K. W. Regulation of insulin secretion by short chain fatty acids. Nature. 1968 Mar 2;217(5131):853–853. doi: 10.1038/217853a0. [DOI] [PubMed] [Google Scholar]
- Turtle J. R., Littleton G. K., Kipnis D. M. Stimulation of insulin secretion by theophylline. Nature. 1967 Feb 18;213(5077):727–728. doi: 10.1038/213727a0. [DOI] [PubMed] [Google Scholar]
- WICK A. N., DRURY D. R., NAKADA H. I., WOLFE J. B. Localization of the primary metabolic block produced by 2-deoxyglucose. J Biol Chem. 1957 Feb;224(2):963–969. [PubMed] [Google Scholar]
- WORK E. The isolation of alpha epsilon-Diaminopimelic acid from Corynebacterium diphtheriae and Mycobacterium tuberculosis. Biochem J. 1951 Jun;49(1):17–23. doi: 10.1042/bj0490017. [DOI] [PMC free article] [PubMed] [Google Scholar]