ABSTRACT
GPR40 is a G-protein-coupled receptor expressed primarily in pancreatic islets and intestinal L-cells that has been a target of significant recent therapeutic interest for type II diabetes. Activation of GPR40 by partial agonists elicits insulin secretion only in the presence of elevated blood glucose levels, minimizing the risk of hypoglycemia. GPR40 agoPAMs have shown superior efficacy to partial agonists as assessed in a glucose tolerability test (GTT). Herein, we report the discovery and optimization of a series of potent, selective GPR40 agoPAMs. Compound 24 demonstrated sustained glucose lowering in a chronic study of Goto Kakizaki rats, showing no signs of tachyphylaxis for this mechanism.
ABSTRACT
The discovery of novel 4-hydroxy-2-(heterocyclic)pyrimidine-5-carboxamide inhibitors of hypoxia-inducible factor (HIF) prolyl hydroxylases (PHD) is described. These are potent, selective, orally bioavailable across several species, and active in stimulating erythropoiesis. Mouse and rat studies showed hematological changes with elevations of plasma EPO and circulating reticulocytes following single oral dose administration, while 4-week q.d. po administration in rat elevated hemoglobin levels. A major focus of the optimization process was to decrease the long half-life observed in higher species with early compounds. These efforts led to the identification of 28 (MK-8617), which has advanced to human clinical trials for anemia.
Subject(s)
Anemia/drug therapy , Drug Discovery , Enzyme Inhibitors/pharmacology , Hypoxia-Inducible Factor-Proline Dioxygenases/antagonists & inhibitors , Pyridazines/pharmacology , Pyrimidines/pharmacology , Administration, Oral , Anemia/enzymology , Animals , Dose-Response Relationship, Drug , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemistry , Humans , Hypoxia-Inducible Factor-Proline Dioxygenases/metabolism , Mice , Mice, Inbred C57BL , Models, Molecular , Molecular Structure , Pyridazines/administration & dosage , Pyridazines/chemistry , Pyrimidines/administration & dosage , Pyrimidines/chemistry , Rats , Rats, Sprague-Dawley , Structure-Activity RelationshipABSTRACT
The synthesis, SAR, binding affinities and pharmacokinetic profiles are described for a series of cyclohexane-based prolylcarboxypeptidase (PrCP) inhibitors discovered by high throughput screening. Compounds show high levels of ex vivo target engagement in mouse plasma 20 h post oral dose.
Subject(s)
Carboxypeptidases/antagonists & inhibitors , Cyclohexanes/chemistry , Cyclohexanes/pharmacology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Animals , Cyclohexanes/pharmacokinetics , Drug Discovery , Male , Mice , Mice, Inbred C57BL , Molecular Structure , Obesity/drug therapy , Structure-Activity RelationshipABSTRACT
LH-21 (5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-3-hexyl-1H-1,2,4-triazole) was previously reported as a neutral antagonist at the cannabinoid CB1 receptor which, despite its reported poor ability to penetrate into the brain, suppressed food intake and body weight in rats by intraperitoneal administration. In the present study, we studied the mechanism of action of LH-21 by characterizing its in vitro pharmacological properties and in vivo efficacy. LH-21 inhibited the binding of [3H]CP55940 to cloned human and rat CB1 receptors with IC50 values of 631+/-98 nM, and 690+/-41 nM, respectively, and acted as an inverse agonist in a cAMP functional assay using cultured cells expressing human, rat or mouse CB1 receptor. The compound was shown to be brain-penetrant in rats by intravenous administration. Importantly, a single dose of LH-21 (60 mg/kg, i.p.) caused a similar suppression of overnight food intake and body weight gain in wild-type and CB1 receptor knockout mice. Our results suggest that LH-21 is a low affinity inverse agonist for the CB1 receptor and does not act on the CB1 receptor to inhibit food intake in mice.
