title: Beneficial effect of a chronic treatment with rimonabant on pancreatic function and beta-cell morphology in Zucker Fatty rats.
abstract: Recent studies suggested the involvement of the endocannabinoid pathway on insulin secretion in RINm5F cells or rat islets. Animal and clinical studies have reported beneficial effects of the selective cannabinoid 1 receptor antagonist rimonabant on glucose homeostasis. The aim of this study was to investigate the in vivo effects of rimonabant on pancreatic function in Zucker Fatty rats. Zucker Fatty rats were treated with rimonabant (10 mg kg(-1) day(-1)) or vehicle for up to 3 months. Pancreatic function was assessed by oral glucose tolerance test and by static incubation of islets in the presence of different glucose concentrations. Islet morphology was assessed by immuno-histochemistry on pancreatic sections. After 3 months, there was no difference in fasting glycaemia or AUC(glucose) during oral glucose tolerance test between rimonabant- and vehicle-treated animals. However, vehicle-treated rats developed a marked hyperinsulinaemia with time in contrast to rimonabant-treated animals, which maintained at 3 months significantly lower fasting insulin levels (7.76+/-0.67 microg l(-1) vs. 5.59+/-0.59 microg l(-1), P<0.01) and lower AUC(insulin) (1380+/-98 microg l(-1)min vs. 926+/-58 microg l(-1)min, respectively, P<0.001). In static incubation, rimonabant significantly decreased insulin secretion in response to low glucose concentration (3 months: 7.68+/-1.29 vs. 12.25+/-2.01 microg l(-1) 5 islets(-1) 45 min(-1) in rimonabant and vehicle respectively, P<0.01), resulting in a trend to increase stimulation index in the presence of 16.7 mM glucose (10.64+/-0.92 vs. 8.52+/-1.70 respectively). Morphological analysis at 3 months showed that rimonabant reduced islet-cell surface (-60%) and the percentage of disorganized islets (-54%).In conclusion, our data suggest that rimonabant has a protective role against the development of hyperinsulinaemia, beta-cell dysfunction and islet modification in Zucker Fatty rats.
authors.affiliation: Sanofi-Aventis R&D, Discovery Research Metabolism Department, Rueil-Malmaison, France. valerie.duvivier@sanofi-aventis.com
authors.forename: Valérie F
authors.initials: VF
authors.lastname: Duvivier
authors.forename: Laure
authors.initials: L
authors.lastname: Delafoy-Plasse
authors.forename: Véronique
authors.initials: V
authors.lastname: Delion
authors.forename: Patricia
authors.initials: P
authors.lastname: Lechevalier
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Le Bail
authors.forename: Etienne
authors.initials: E
authors.lastname: Guillot
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Pruniaux
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Galzin
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism; D002417:Cattle; D004435:Eating / Q000187:drug effects; D005215:Fasting; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005951:Glucose Tolerance Test; D006706:Homeostasis / Q000187:drug effects; D006946:Hyperinsulinism / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D006965:Hyperplasia / Q000517:prevention & control; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D010179:Pancreas / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology* / Q000503:physiopathology; D010880:Piperidines / Q000494:pharmacology* / Q000627:therapeutic use; D011720:Pyrazoles / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D011924:Rats, Zucker; D000077285:Rimonabant; D013997:Time Factors
chemical_list: D063385:Cannabinoid Receptor Modulators; D007328:Insulin; D010880:Piperidines; D011720:Pyrazoles; D005947:Glucose; D000077285:Rimonabant