MLR 1023

Tolimidone is a potent and selective allosteric activator of Lyn kinase with an EC50 of 63 nM.

In Vitro:Incubation of Tolimidone (MLR-1023) with Lyn kinase elicits a repeatable 50% increase in enzyme activity. Tolimidone elicits a concentration-dependent increase in Lyn kinase activation with a 2.3- and 2.1-fold increase achieved at concentrations of 3 and 10 μM, respectively. Inclusion of Tolimidone (100 μM) increases Lyn kinase activity by 3-fold at each ATP concentration tested (Vmax=2601 U/mg). Tolimidone-mediated activation of Lyn kinase increases in proportion to the length of preincubation period in the absence of ATP[1].

In Vivo:Administration of Tolimidone (MLR-1023) (30 mg/kg i.p.) significantly (p<0.05) lowers blood glucose levels to 148 and 158 mg/dL, 30 and 90 min after administration, respectively. Tolimidone significantly increases adipocyte differentiation and adiponectin production by 3.7- and 19-fold, respectively[1]. Tolimidone elicits a dose-dependent potentiation of the insulin response, with a maximal effect observed with a dose level of 30 mg/kg[2].

References:
[1]. Saporito MS, et al. MLR-1023 is a potent and selective allosteric activator of Lyn kinase in vitro that improves glucose tolerance in vivo. J Pharmacol Exp Ther. 2012 Jul;342(1):15-22. [2]. Ochman AR, et al. The Lyn kinase activator MLR-1023 is a novel insulin receptor potentiator that elicits a rapid-onset and durable improvement in glucose homeostasis in animal models of type 2 diabetes. J Pharmacol Exp Ther. 2012 Jul;342(1):23-32.

MLR-1023 is a potent and selective allosteric activator of Lyn kinase in vitro that improves glucose tolerance in vivo.[Pubmed:22473614]

J Pharmacol Exp Ther. 2012 Jul;342(1):15-22.

2(1H)-pyrimidinone,5-(3-methylphenoxy) (MLR-1023) is a candidate for the treatment of type 2 diabetes. The current studies were aimed at determining the mechanism by which MLR-1023 mediates glycemic control. In these studies, we showed that MLR-1023 reduced blood glucose levels without increasing insulin secretion in vivo. We have further determined that MLR-1023 did not activate peroxisome proliferator-activated alpha, delta, and gamma receptors or glucagon-like peptide-1 receptors or inhibit dipeptidyl peptidase-4 or alpha-glucosidase enzyme activity. However, in an in vitro broad kinase screen MLR-1023 activated the nonreceptor-linked Src-related tyrosine kinase Lyn. MLR-1023 increased the V(max) of Lyn with an EC(50) of 63 nM. This Lyn kinase activation was ATP binding site independent, indicating that MLR-1023 regulated the kinase through an allosteric mechanism. We have established a link between Lyn activation and blood glucose lowering with studies showing that the glucose-lowering effects of MLR-1023 were abolished in Lyn knockout mice, consistent with existing literature linking Lyn kinase and the insulin-signaling pathway. In summary, these studies describe MLR-1023 as a unique blood glucose-lowering agent and show that MLR-1023-mediated blood glucose lowering depends on Lyn kinase activity. These results, coupled with other results (J Pharmacol Exp Ther 342:23-32, 2012), suggest that MLR-1023 and Lyn kinase activation may be a new treatment modality for type 2 diabetes.

The Lyn kinase activator MLR-1023 is a novel insulin receptor potentiator that elicits a rapid-onset and durable improvement in glucose homeostasis in animal models of type 2 diabetes.[Pubmed:22431203]

J Pharmacol Exp Ther. 2012 Jul;342(1):23-32.

MLR-1023 [Tolimidone; CP-26154; 2(1H)-pyrimidinone, 5-(3-methylphenoxy)] is an allosteric Lyn kinase activator that reduces blood glucose levels in mice subjected to an oral glucose tolerance test (J Pharmacol Exp Ther 342:15-22, 2012). The current studies were designed to define the role of insulin in MLR-1023-mediated blood glucose lowering, to evaluate it in animal models of type 2 diabetes, and to compare it to the activities of selected existing diabetes therapeutics. Results from these studies show that in an acute oral glucose tolerance test MLR-1023 evoked a dose-dependent blood glucose-lowering response that was equivalent in magnitude to that of metformin without eliciting a hypoglycemic response. In streptozotocin-treated, insulin-depleted mice, MLR-1023 administration did not affect blood glucose levels. However, MLR-1023 potentiated the glucose-lowering activity of exogenously administered insulin, showing that MLR-1023-mediated blood glucose lowering was insulin-dependent. In a hyperinsulinemic/euglycemic clamp study, orally administered MLR-1023 increased the glucose infusion rate required to sustain blood glucose levels, demonstrating that MLR-1023 increased insulin receptor sensitivity. In chronically treated db/db mice, MLR-1023 elicited a dose-dependent and durable glucose-lowering effect, reduction in HbA1c levels and preservation of pancreatic beta-cells. The magnitude of effect was equivalent to that seen with rosiglitazone but with a faster onset of action and without causing weight gain. These studies show that MLR-1023 is an insulin receptor-potentiating agent that produces a rapid-onset and durable blood glucose-lowering activity in diabetic animals.