Abstract
Wistar rats develop glucose intolerance and have a diminished insulin response to glucose with age. The aim of this study was to investigate if these changes were reversible with glucagon-like peptide-1 (GLP-1), a peptide that we have previously shown could increase insulin mRNA and total insulin content in insulinoma cells. We infused 1.5 pmol/ kg-1.min-1 GLP-1 subcutaneously using ALZET microosmotic pumps into 22-mo-old Wistar rats for 48 h. Rat infused with either GLP-1 or saline were then subjected to an intraperitoneal glucose (1 g/kg body weight) tolerance test, 2 h after removing the pump. 15 min after the intraperitoneal glucose, GLP-1-treated animals had lower plasma glucose levels (9.04+/-0.92 mmol/liter, P < 0.01) than saline-treated animals (11.61+/-0.23 mmol/liter). At 30 min the plasma glucose was still lower in the GLP-1-treated animals (8.61+/-0.39 mmol/liter, P < 0.05) than saline-treated animals (10.36+/-0.43 mmol/liter). This decrease in glucose levels was reflected in the higher insulin levels attained in the GLP-1-treated animals (936+/-163 pmol/liter vs. 395+/-51 pmol/liter, GLP-1 vs. saline, respectively, P < 0.01), detected 15 min after glucose injection. GLP-1 treatment also increased pancreatic insulin, GLUT2, and glucokinase mRNA in the old rats. The effects of GLP-1 were abolished by simultaneous infusion of exendin [9-39], a specific antagonist of GLP-1. GLP-1 is therefore able to reverse some of the known defects that arise in the beta cell of the pancreas of Wistar rats, not only by increasing insulin secretion but also by inducing significant changes at the molecular level.
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- Arner P., Pollare T., Lithell H. Different aetiologies of type 2 (non-insulin-dependent) diabetes mellitus in obese and non-obese subjects. Diabetologia. 1991 Jul;34(7):483–487. doi: 10.1007/BF00403284. [DOI] [PubMed] [Google Scholar]
- Chirgwin J. M., Przybyla A. E., MacDonald R. J., Rutter W. J. Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease. Biochemistry. 1979 Nov 27;18(24):5294–5299. doi: 10.1021/bi00591a005. [DOI] [PubMed] [Google Scholar]
- Drucker D. J., Philippe J., Mojsov S., Chick W. L., Habener J. F. Glucagon-like peptide I stimulates insulin gene expression and increases cyclic AMP levels in a rat islet cell line. Proc Natl Acad Sci U S A. 1987 May;84(10):3434–3438. doi: 10.1073/pnas.84.10.3434. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Egan J. M., Asplin C. M., Drumheller M. A., Kerrigan J. R., Scott J., Martha P. M., Jr, Evans W. S. Glucose-stimulated insulin release by individual pancreatic beta cells: potentiation by glyburide. Proc Soc Exp Biol Med. 1991 Feb;196(2):203–209. doi: 10.3181/00379727-196-43180. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Elahi D., McAloon-Dyke M., Fukagawa N. K., Meneilly G. S., Sclater A. L., Minaker K. L., Habener J. F., Andersen D. K. The insulinotropic actions of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (7-37) in normal and diabetic subjects. Regul Pept. 1994 Apr 14;51(1):63–74. doi: 10.1016/0167-0115(94)90136-8. [DOI] [PubMed] [Google Scholar]
- Elahi D., Muller D. C., Andersen D. K., Tobin J. D., Andres R. The effect of age and glucose concentration on insulin secretion by the isolated perfused rat pancreas. Endocrinology. 1985 Jan;116(1):11–16. doi: 10.1210/endo-116-1-11. [DOI] [PubMed] [Google Scholar]
- Fehmann H. C., Habener J. F. Insulinotropic hormone glucagon-like peptide-I(7-37) stimulation of proinsulin gene expression and proinsulin biosynthesis in insulinoma beta TC-1 cells. Endocrinology. 1992 Jan;130(1):159–166. doi: 10.1210/endo.130.1.1309325. [DOI] [PubMed] [Google Scholar]
- Ferber S., BeltrandelRio H., Johnson J. H., Noel R. J., Cassidy L. E., Clark S., Becker T. C., Hughes S. D., Newgard C. B. GLUT-2 gene transfer into insulinoma cells confers both low and high affinity glucose-stimulated insulin release. Relationship to glucokinase activity. J Biol Chem. 1994 Apr 15;269(15):11523–11529. [PubMed] [Google Scholar]
- Glisin V., Crkvenjakov R., Byus C. Ribonucleic acid isolated by cesium chloride centrifugation. Biochemistry. 1974 Jun 4;13(12):2633–2637. doi: 10.1021/bi00709a025. [DOI] [PubMed] [Google Scholar]
- Gutniak M., Orskov C., Holst J. J., Ahrén B., Efendic S. Antidiabetogenic effect of glucagon-like peptide-1 (7-36)amide in normal subjects and patients with diabetes mellitus. N Engl J Med. 1992 May 14;326(20):1316–1322. doi: 10.1056/NEJM199205143262003. [DOI] [PubMed] [Google Scholar]
- Holz G. G., 4th, Kühtreiber W. M., Habener J. F. Pancreatic beta-cells are rendered glucose-competent by the insulinotropic hormone glucagon-like peptide-1(7-37). Nature. 1993 Jan 28;361(6410):362–365. doi: 10.1038/361362a0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hosokawa Y. A., Hosokawa H., Chen C., Leahy J. L. Mechanism of impaired glucose-potentiated insulin secretion in diabetic 90% pancreatectomy rats. Study using glucagonlike peptide-1 (7-37). J Clin Invest. 1996 Jan 1;97(1):180–186. doi: 10.1172/JCI118387. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leahy J. L. Natural history of beta-cell dysfunction in NIDDM. Diabetes Care. 1990 Sep;13(9):992–1010. doi: 10.2337/diacare.13.9.992. [DOI] [PubMed] [Google Scholar]
- Matschinsky F. M. Glucokinase as glucose sensor and metabolic signal generator in pancreatic beta-cells and hepatocytes. Diabetes. 1990 Jun;39(6):647–652. doi: 10.2337/diab.39.6.647. [DOI] [PubMed] [Google Scholar]
- Montrose-Rafizadeh C., Egan J. M., Roth J. Incretin hormones regulate glucose-dependent insulin secretion in RIN 1046-38 cells: mechanisms of action. Endocrinology. 1994 Aug;135(2):589–594. doi: 10.1210/endo.135.2.8033807. [DOI] [PubMed] [Google Scholar]
- Mueckler M. Family of glucose-transporter genes. Implications for glucose homeostasis and diabetes. Diabetes. 1990 Jan;39(1):6–11. doi: 10.2337/diacare.39.1.6. [DOI] [PubMed] [Google Scholar]
- Nadiv O., Cohen O., Zick Y. Defects of insulin's signal transduction in old rat livers. Endocrinology. 1992 Mar;130(3):1515–1524. doi: 10.1210/endo.130.3.1311243. [DOI] [PubMed] [Google Scholar]
- Nathan D. M., Schreiber E., Fogel H., Mojsov S., Habener J. F. Insulinotropic action of glucagonlike peptide-I-(7-37) in diabetic and nondiabetic subjects. Diabetes Care. 1992 Feb;15(2):270–276. doi: 10.2337/diacare.15.2.270. [DOI] [PubMed] [Google Scholar]
- Nauck M. A., Heimesaat M. M., Orskov C., Holst J. J., Ebert R., Creutzfeldt W. Preserved incretin activity of glucagon-like peptide 1 [7-36 amide] but not of synthetic human gastric inhibitory polypeptide in patients with type-2 diabetes mellitus. J Clin Invest. 1993 Jan;91(1):301–307. doi: 10.1172/JCI116186. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nauck M. A., Kleine N., Orskov C., Holst J. J., Willms B., Creutzfeldt W. Normalization of fasting hyperglycaemia by exogenous glucagon-like peptide 1 (7-36 amide) in type 2 (non-insulin-dependent) diabetic patients. Diabetologia. 1993 Aug;36(8):741–744. doi: 10.1007/BF00401145. [DOI] [PubMed] [Google Scholar]
- Orskov C. Glucagon-like peptide-1, a new hormone of the entero-insular axis. Diabetologia. 1992 Aug;35(8):701–711. [PubMed] [Google Scholar]
- Perfetti R., Rafizadeh C. M., Liotta A. S., Egan J. M. Age-dependent reduction in insulin secretion and insulin mRNA in isolated islets from rats. Am J Physiol. 1995 Dec;269(6 Pt 1):E983–E990. doi: 10.1152/ajpendo.1995.269.6.E983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Perfetti R., Wang Y., Shuldiner A. R., Egan J. M. Molecular investigation of age-related changes in mouse endocrine pancreas. J Gerontol A Biol Sci Med Sci. 1996 Sep;51(5):B331–B336. doi: 10.1093/gerona/51a.5.b331. [DOI] [PubMed] [Google Scholar]
- Pilkis S. J., Weber I. T., Harrison R. W., Bell G. I. Glucokinase: structural analysis of a protein involved in susceptibility to diabetes. J Biol Chem. 1994 Sep 2;269(35):21925–21928. [PubMed] [Google Scholar]
- Porte D., Jr Banting lecture 1990. Beta-cells in type II diabetes mellitus. Diabetes. 1991 Feb;40(2):166–180. doi: 10.2337/diab.40.2.166. [DOI] [PubMed] [Google Scholar]
- Thorens B., Waeber G. Glucagon-like peptide-I and the control of insulin secretion in the normal state and in NIDDM. Diabetes. 1993 Sep;42(9):1219–1225. doi: 10.2337/diab.42.9.1219. [DOI] [PubMed] [Google Scholar]
- Thorens B., Wu Y. J., Leahy J. L., Weir G. C. The loss of GLUT2 expression by glucose-unresponsive beta cells of db/db mice is reversible and is induced by the diabetic environment. J Clin Invest. 1992 Jul;90(1):77–85. doi: 10.1172/JCI115858. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Unger R. H. Diabetic hyperglycemia: link to impaired glucose transport in pancreatic beta cells. Science. 1991 Mar 8;251(4998):1200–1205. doi: 10.1126/science.2006409. [DOI] [PubMed] [Google Scholar]
- Valera A., Solanes G., Fernández-Alvarez J., Pujol A., Ferrer J., Asins G., Gomis R., Bosch F. Expression of GLUT-2 antisense RNA in beta cells of transgenic mice leads to diabetes. J Biol Chem. 1994 Nov 18;269(46):28543–28546. [PubMed] [Google Scholar]
- Waeber G., Thompson N., Nicod P., Bonny C. Transcriptional activation of the GLUT2 gene by the IPF-1/STF-1/IDX-1 homeobox factor. Mol Endocrinol. 1996 Nov;10(11):1327–1334. doi: 10.1210/mend.10.11.8923459. [DOI] [PubMed] [Google Scholar]
- Wang S. Y., Halban P. A., Rowe J. W. Effects of aging on insulin synthesis and secretion. Differential effects on preproinsulin messenger RNA levels, proinsulin biosynthesis, and secretion of newly made and preformed insulin in the rat. J Clin Invest. 1988 Jan;81(1):176–184. doi: 10.1172/JCI113291. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang S. Y., Rowe J. W. Age-related impairment in the short term regulation of insulin biosynthesis by glucose in rat pancreatic islets. Endocrinology. 1988 Aug;123(2):1008–1013. doi: 10.1210/endo-123-2-1008. [DOI] [PubMed] [Google Scholar]
- Wang Y., Egan J. M., Raygada M., Nadiv O., Roth J., Montrose-Rafizadeh C. Glucagon-like peptide-1 affects gene transcription and messenger ribonucleic acid stability of components of the insulin secretory system in RIN 1046-38 cells. Endocrinology. 1995 Nov;136(11):4910–4917. doi: 10.1210/endo.136.11.7588224. [DOI] [PubMed] [Google Scholar]
- Wang Y., Montrose-Rafizadeh C., Adams L., Raygada M., Nadiv O., Egan J. M. GIP regulates glucose transporters, hexokinases, and glucose-induced insulin secretion in RIN 1046-38 cells. Mol Cell Endocrinol. 1996 Jan 15;116(1):81–87. doi: 10.1016/0303-7207(95)03701-2. [DOI] [PubMed] [Google Scholar]
- Wang Z., Wang R. M., Owji A. A., Smith D. M., Ghatei M. A., Bloom S. R. Glucagon-like peptide-1 is a physiological incretin in rat. J Clin Invest. 1995 Jan;95(1):417–421. doi: 10.1172/JCI117671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Widmann C., Dolci W., Thorens B. Desensitization and phosphorylation of the glucagon-like peptide-1 (GLP-1) receptor by GLP-1 and 4-phorbol 12-myristate 13-acetate. Mol Endocrinol. 1996 Jan;10(1):62–75. doi: 10.1210/mend.10.1.8838146. [DOI] [PubMed] [Google Scholar]