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Lynch CJ, Zhou Q, Shyng SL, Heal DJ, Cheetham SC, Dickinson K, Gregory P, Firnges M, Nordheim U, Goshorn S, Reiche D, Turski L, Antel J. Some cannabinoid receptor ligands and their distomers are direct-acting openers of SUR1 K(ATP) channels. Am J Physiol Endocrinol Metab 2012; 302:E540-51. [PMID: 22167524 PMCID: PMC3311290 DOI: 10.1152/ajpendo.00250.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Here, we examined the chronic effects of two cannabinoid receptor-1 (CB1) inverse agonists, rimonabant and ibipinabant, in hyperinsulinemic Zucker rats to determine their chronic effects on insulinemia. Rimonabant and ibipinabant (10 mg·kg⁻¹·day⁻¹) elicited body weight-independent improvements in insulinemia and glycemia during 10 wk of chronic treatment. To elucidate the mechanism of insulin lowering, acute in vivo and in vitro studies were then performed. Surprisingly, chronic treatment was not required for insulin lowering. In acute in vivo and in vitro studies, the CB1 inverse agonists exhibited acute K channel opener (KCO; e.g., diazoxide and NN414)-like effects on glucose tolerance and glucose-stimulated insulin secretion (GSIS) with approximately fivefold better potency than diazoxide. Followup studies implied that these effects were inconsistent with a CB1-mediated mechanism. Thus effects of several CB1 agonists, inverse agonists, and distomers during GTTs or GSIS studies using perifused rat islets were unpredictable from their known CB1 activities. In vivo rimonabant and ibipinabant caused glucose intolerance in CB1 but not SUR1-KO mice. Electrophysiological studies indicated that, compared with diazoxide, 3 μM rimonabant and ibipinabant are partial agonists for K channel opening. Partial agonism was consistent with data from radioligand binding assays designed to detect SUR1 K(ATP) KCOs where rimonabant and ibipinabant allosterically regulated ³H-glibenclamide-specific binding in the presence of MgATP, as did diazoxide and NN414. Our findings indicate that some CB1 ligands may directly bind and allosterically regulate Kir6.2/SUR1 K(ATP) channels like other KCOs. This mechanism appears to be compatible with and may contribute to their acute and chronic effects on GSIS and insulinemia.
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MESH Headings
- ATP-Binding Cassette Transporters/agonists
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Allosteric Regulation
- Animals
- Anti-Obesity Agents/adverse effects
- Anti-Obesity Agents/chemistry
- Anti-Obesity Agents/pharmacology
- Anti-Obesity Agents/therapeutic use
- Cell Line, Transformed
- Chlorocebus aethiops
- Cricetinae
- Glucose Intolerance/chemically induced
- Glucose Intolerance/metabolism
- Humans
- Hypoglycemic Agents/adverse effects
- Hypoglycemic Agents/chemistry
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Islets of Langerhans/drug effects
- Islets of Langerhans/metabolism
- Ligands
- Male
- Membrane Transport Modulators/adverse effects
- Membrane Transport Modulators/chemistry
- Membrane Transport Modulators/pharmacology
- Membrane Transport Modulators/therapeutic use
- Mice
- Mice, Knockout
- Mice, Obese
- Potassium Channels, Inwardly Rectifying/agonists
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Rats
- Rats, Zucker
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptors, Drug/agonists
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Recombinant Proteins/agonists
- Recombinant Proteins/antagonists & inhibitors
- Recombinant Proteins/metabolism
- Stereoisomerism
- Sulfonylurea Receptors
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Affiliation(s)
- Christopher J Lynch
- Dept. of Cellular & Molecular Physiology, Pennsylvania State College of Medicine, Hershey, PA 17033, USA.
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Balamurugan R, Duraipandiyan V, Ignacimuthu S. Antidiabetic activity of γ-sitosterol isolated from Lippia nodiflora L. in streptozotocin induced diabetic rats. Eur J Pharmacol 2011; 667:410-8. [DOI: 10.1016/j.ejphar.2011.05.025] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 04/26/2011] [Accepted: 05/11/2011] [Indexed: 12/23/2022]
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3
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Morgan NG. Imidazoline receptors: new targets for antihyperglycaemic drugs. Expert Opin Investig Drugs 2005; 8:575-84. [PMID: 15992117 DOI: 10.1517/13543784.8.5.575] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In both animal models of Type 2 diabetes and in man, it has been evident for many years that certain imidazoline drugs can stimulate insulin secretion and improve glycaemia. This suggests that they may be useful new reagents for use in the management of Type 2 diabetes. However, despite their promise, no imidazoline compound has yet come into clinical use as an effective therapeutic agent in diabetes. This should not be taken as evidence of a flaw in the basic hypothesis, but derives, in part, from continuing ignorance about the molecular characteristics of imidazoline binding proteins, and the precise structure-activity relationships of their ligands. In this review, the mode of action of antihyperglycaemic imidazoline compounds is considered, and the possibility discussed that these agents may interact with a unique subtype of imidazoline binding site associated with ATP-sensitive potassium channels. The functional consequences of this interaction are summarised together with evidence that the binding site may actually lie within the channel complex. Additional data implicating the participation of alpha2-adrenoceptors in some actions of imidazolines are evaluated, and examples of relevant drugs having encouraging therapeutic profiles are highlighted. The possibility that some anti-diabetic imidazoline reagents may exert extra-pancreatic effects is also considered. Overall, the article aims to highlight important developments within the field but also draws attention to those areas where controversy remains.
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Affiliation(s)
- N G Morgan
- School of Life Sciences, Keele University, Staffordshire, ST5 5BG, UK.
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4
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Nourparvar A, Bulotta A, Di Mario U, Perfetti R. Novel strategies for the pharmacological management of type 2 diabetes. Trends Pharmacol Sci 2004; 25:86-91. [PMID: 15102494 DOI: 10.1016/j.tips.2003.12.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Type 2 diabetes is characterized by high concentrations of glucose in the blood, which is caused by decreased secretion of insulin from the pancreas and decreased insulin action. This condition is prevalent worldwide and is associated with morbidity and mortality secondary to complications such as myocardial infarction, stroke and end-stage renal disease. The importance of tight control of blood glucose in either preventing or delaying the progression of complications is recognized. Currently, there are many therapeutic options to treat hyperglycemia in type 2 diabetes. However, tight control is difficult to achieve and is often associated with side-effects. Recent advances in understanding insulin secretion, action and signaling have led to the development of new pharmacological agents. In this article, we review new molecules that are promising candidates for the future management of diabetes, focusing on their mechanism of action, efficacy, safety profile and potential benefits compared with pharmacological agents that are available currently.
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Affiliation(s)
- Arash Nourparvar
- Division of Endocrinology and Metabolism, Cedars-Sinai Medical Center, 8723 Alden Drive, SSB # 290, Los Angeles, CA 90048, USA
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5
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Maroo J, Vasu VT, Aalinkeel R, Gupta S. Glucose lowering effect of aqueous extract of Enicostemma littorale Blume in diabetes: a possible mechanism of action. JOURNAL OF ETHNOPHARMACOLOGY 2002; 81:317-320. [PMID: 12127231 DOI: 10.1016/s0378-8741(02)00095-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycemia. Enicostemma littorale Blume is a small herb and recently we have reported its blood glucose lowering potential in alloxan induced diabetic rats. A single dose of aqueous extract of E. littorale (15 g dry plant equivalent extract per kg) had shown significant increase in the serum insulin levels in alloxan-induced diabetic rats at 8 h. The insulinotropic action of aqueous extract of E. littorale was further investigated using rat pancreatic islets. Extract has the potential to enhance glucose-induced insulin release at 11.1 mM glucose from isolated rat pancreatic islets and was partially able to reverse the effect of diazoxide (0.25 mM). Incubation with Ca(2+) chelator (EGTA) and Ca(2+) channel blocker (nimodipine) did not affect the glucose-induced insulin release augmented by the extract. Above results suggest the glucose lowering effect of aqueous extract of E. littorale to be associated with potentiation of glucose-induced insulin release through K(+)-ATP channel dependent pathway but did not require Ca(2+) influx.
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Affiliation(s)
- Jyoti Maroo
- Department of Biochemistry, Faculty of Science, M. S. University, Baroda Gujarat 390 002, India
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6
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Abstract
The onset of type 2 diabetes is characterized by two determining factors: the insufficient ability to secrete insulin and/or the resistance to its biological action. Although in a very small proportion of individuals, one of those two metabolic abnormalities is the leading cause of diabetes, in most subjects, the coexistence of both appears to be necessary for the clinical manifestation of diabetes. Current biomedical research continues to clarify the relative contributions of these defects to the pathogenesis of type 2 diabetes, and novel pharmacological agents are specifically designed to correct either the impaired insulin secretory activity or the resistance to the action of insulin. The aim of this article is to provide a critical review of new sulfonylurea and non-sulfonylurea drugs that have been recently introduced for the treatment of diabetes, as well as drugs that are still under investigation and are likely to be made available in the near future.
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Affiliation(s)
- R Perfetti
- Division of Diabetes, Endocrinology and Metabolism, Room B-131, Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA.
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7
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McClenaghan NH, Ball AJ, Flatt PR. Induced desensitization of the insulinotropic effects of antidiabetic drugs, BTS 67 582 and tolbutamide. Br J Pharmacol 2000; 130:478-84. [PMID: 10807689 PMCID: PMC1572067 DOI: 10.1038/sj.bjp.0703306] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Acute and chronic mechanisms of action of novel insulinotropic antidiabetic drug, BTS 67 582 (1, 1-dimethyl-2-(2-morpholinophenyl)guanidine fumarate), were examined in the stable cultured BRIN-BD11 cell line. BTS 67 582 (100 - 400 microM) stimulated a concentration-dependent increase (P<0.01) in insulin release at both non-stimulatory (1.1 mM) and stimulatory (8. 4 mM) glucose. Long-term exposure (3 - 18 h) to 100 microM BTS 67 582 in culture time-dependently decreased subsequent responsiveness to acute challenge with 200 microM BTS 67 582 or 200 microM tolbutamide at 12 - 18 h (P<0.001). Similarly 3 - 18 h culture with the sulphonylurea, tolbutamide (100 microM), also effectively suppressed subsequent insulinotropic responses to both BTS 67 582 and tolbutamide. Culture with 100 microM BTS 67 582 or 100 microM tolbutamide did not affect basal insulin secretion, cellular insulin content, or cell viability and exerted no influence on the secretory responsiveness to 200 microM of the imidazoline, efaroxan. While 18 h BTS 67 582 culture did not affect the insulin-releasing actions (P<0.001) of 16.7 mM glucose, 10 mM arginine, 30 mM KCl, 25 microM forskolin or 10 nM phorbol-12-myristate 13-acetate (PMA), significant inhibition (P<0.001) of the insulinotropic effects of 10 mM 2-ketoisocaproic acid (KIC) and 10 mM alanine were observed. These data suggest that BTS 67 582 shares a common signalling pathway to sulphonylurea but not imidazoline drugs. Desensitization of drug action may provide an important approach to dissect sites of action of novel and established insulinotropic antidiabetic agents.
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Affiliation(s)
- N H McClenaghan
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA.
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Pelé-Tounian A, Chan SL, Rondu F, Le Bihan G, Giroix MH, Lamouri A, Touboul E, Pfeiffer B, Manechez D, Renard P, Guardiola-Lemaître B, Godfroid JJ, Pénicaud L, Morgan NG, Ktorza A. Effect of the new imidazoline derivative S-22068 (PMS 847) on insulin secretion in vitro and glucose turnover in vivo in rats. Eur J Pharmacol 1999; 377:81-7. [PMID: 10448930 DOI: 10.1016/s0014-2999(99)00395-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We have investigated the possible mechanisms underlying the antihyperglycaemic effect of the imidazoline derivative S-22068. In vitro, in the presence of 5 mmol/l glucose, S-22068 (100 micromol/l) induced a significant and sustained increase in insulin secretion from isolated, perifused, rat islets and a marked sensitization to a subsequent glucose challenge (10 mmol/l). S-22068 (100 micromol/l was able to antagonize the stimulatory effect of diazoxide on 86Rb efflux from preloaded islets incubated in the presence of 20 mmol/l glucose. Experiments were also performed to investigate whether S-22068 can alter glucose turnover and peripheral insulin sensitivity in vivo in mildly diabetic rats and obese, insulin resistant, Zucker rats. Neither glucose production nor individual tissue glucose utilization was modified by S-22068 in either group of rats. Similar results were obtained whether the studies were performed under basal conditions or during euglycaemic/hyperinsulinemic clamps. The results suggest that S-22068 exerts part of its antihyperglycaemic effect by promoting insulin secretion without alteration of peripheral insulin sensitivity.
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Affiliation(s)
- A Pelé-Tounian
- Laboratoire de Physiopathologie de la Nutrition, Groupe Endocrinologie Métabolique, ESA 7059, Université Paris 7-Denis Diderot, France
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Cooling M, Spencer P, Yates D, Sim M, Jones R. Investigation of the effects of BTS 67 582, a novel antidiabetic agent, in the beagle dog. Drug Dev Res 1999. [DOI: 10.1002/(sici)1098-2299(199907)47:3<137::aid-ddr4>3.0.co;2-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Abstract
BTS 67 582 (1,1-dimethyl-2(2-morpholinophenyl)guanidine fumarate) is being developed as a short-acting anti-diabetic insulin secretagogue. The effect of BTS 67 582 on the phasic pattern of insulin release was assessed in anaesthetized normal rats by measuring arterial plasma insulin concentrations while arterial glucose concentrations were fixed at 6, 8.5 and 12.5 mM. Intravenous BTS 67 582 (10 mg kg(-1)) induced an immediate but transient increase in insulin concentrations which declined by 10 min (first phase). This was followed by a smaller but sustained increase in insulin concentrations (second phase). The increment from basal to peak insulin release (0-2 min) was independent of glucose, but the first phase was maintained for longer and the second phase was greater at the highest concentration of glucose (12.5 mM). BTS 67 582 also extended the first-phase insulin response to a standard intravenous glucose challenge and enhanced the rate of glucose disappearance by approximately 12%. Thus BTS 67 582 causes biphasic stimulation of insulin release and augments the insulin-releasing effect of glucose.
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Affiliation(s)
- D A Storey
- Department of Pharmaceutical and Biological Sciences, Aston University, Birmingham, UK
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11
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Louchami K, Jijakli H, Sener A, Jones RB, Malaisse WJ. Effect of 1,1-dimethyl-2-[2-morpholinophenyl]guanidine fumarate on pancreatic islet function. Eur J Pharmacol 1998; 352:289-97. [PMID: 9716366 DOI: 10.1016/s0014-2999(98)00352-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The modality of the insulinotropic action of 1,1-dimethyl-2-[2-morpholinophenyl]guanidine fumarate (BTS 67 582), a new antidiabetic agent, was investigated in rat pancreatic islets. At a 0.1 mM concentration, which was sufficient to cause a close-to-maximal secretory response, BTS 67 582 failed to affect the utilization and oxidation of exogenous D-glucose, but slightly augmented 14CO2 production from islets prelabelled with either L-[U-14C]glutamine or [U-14C]palmitate. BTS 67 582 (0.1 mM) also failed to affect biosynthetic activity in islets incubated with L-[4-3H]phenylalanine. It augmented insulin release from islets incubated for 90 min in the absence or presence of D-glucose (2.8 to 16.7 mM), this coinciding with stimulation of 45Ca net uptake. In perifused islets deprived of extracellular D-glucose for 45 min, BTS 67 582 (0.1 mM) decreased 86Rb outflow from prelabelled islets, but failed to increase 45Ca efflux and insulin release. In the presence of D-glucose (7.0 mM), BTS 67 582, whilst failing to decrease 86Rb+ outflow, provoked rapid, sustained and rapidly reversible increases of both 45Ca2+ efflux and insulin output. The latter increases were attenuated, but not totally suppressed, in the absence of extracellular Ca2+. BTS 67 582 (0.1 mM) suppressed the inhibitory action of diazoxide (0.25 mM) upon glucose-stimulated insulin release, but nevertheless augmented insulin output from islets incubated in the presence of 90 mM K+. These findings support the view that the insulinotropic action of BTS 67 582 is mainly attributable to the inactivation of ATP-sensitive K+ channels. An intracellular redistribution of Ca2+ ions may also participate, however, to the islet functional response to BTS 67 582.
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Affiliation(s)
- K Louchami
- Laboratory of Experimental Medicine, Brussels Free University, Belgium
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