Glucagon challenge in the rat: a robust method for the in vivo assessment of Glycogen phosphorlyase inhibitor efficacy
| Autor: | Frank Carey, Susan J. G. Loxham, Joanne De Schoolmeester, Joanne Teague, Simon M. Poucher, Andrew V. Turnbull |
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| Rok vydání: | 2006 |
| Předmět: |
Blood Glucose
Male medicine.medical_specialty Glycogenolysis Indoles Pyrrolidines Type 2 diabetes Toxicology Glucagon chemistry.chemical_compound Glycogen phosphorylase Sugar Alcohols In vivo Internal medicine medicine Animals Enzyme Inhibitors Rats Wistar Pharmacology Glycogen business.industry Glycogen Phosphorylase medicine.disease Arabinose Subcutaneous route Rats Rats Zucker Endocrinology chemistry Imino Furanoses Zucker Rats business |
| Zdroj: | Journal of pharmacological and toxicological methods. 55(1) |
| ISSN: | 1056-8719 |
| Popis: | Glycogen phosphorlyase inhibitors (GPi) act on the glycogenolytic pathway decreasing hepatic glucose output, making them potential candidates for Type 2 diabetes treatment. We established a robust in vivo method to assess GPis efficacy utilising glucagon-stimulated glycogenolysis.Blood glucose was monitored in both male AP Wistar and AP Zucker rats using tail prick samples pre- and post intraperitoneal or subcutaneous glucagon administration. The effect of glycogen phosphorylase inhibitors GPi296 (6-60 mg kg(-1) po) and DAB (5 mg kg(-1) po) upon glucose response to subcutaneous glucagon were examined in both strains.In the Wistar rat glucagon induced dose related increases in blood glucose, with the maximum increase occurring 20 min post dose (4.0+/-0.88 mmol l(-1), intraperitoneal; and 2.8+/-0.72 mmol l(-1), subcutaneous, ns). Intraperitoneal glucagon administration produced shorter duration blood glucose elevation than observed with the subcutaneous route of administration. In the Zucker rat, no differences were observed between the 10 and 13 week old rats in response to glucagon (3-200 microg kg(-1) subcutaneous). The maximum blood glucose increase was lower in the Wistar rat compared to the Zucker rats (2.9+/-0.20 vs 7.7+/-1.22 mmol l(-1), P0.0000018). GPi296 and DAB both produced similar inhibition in each strain.Subcutaneous glucagon administration induced more sustained increases in blood glucose than intraperitoneal administration. Blood glucose response to glucagon was higher in the Zucker rat compared to the Wistar rat; there was no difference in inhibition mediated by either GPi296 or DAB between the two strains. We believe that subcutaneous glucagon administration produces a robust model for the assessment of GPis in either rat strain. |
| Databáze: | OpenAIRE |
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