The peptide hormone glucagon-like peptide (GLP)-1 has important actions resulting in glucose lowering along with weight loss in patients with type 2 diabetes. As a peptide hormone, GLP-1 has to be administered by injection. Only a few small-molecule agonists to peptide hormone receptors have been described and none in the B family of the G protein coupled receptors to which the GLP-1 receptor belongs. We have discovered a series of small molecules known as ago-allosteric modulators selective for the human GLP-1 receptor. These compounds act as both allosteric activators of the receptor and independent agonists. Potency of GLP-1 was not changed by the allosteric agonists, but affinity of GLP-1 for the receptor was increased. The most potent compound identified stimulates glucose-dependent insulin release from normal mouse islets but, importantly, not from GLP-1 receptor knockout mice. Also, the compound stimulates insulin release from perfused rat pancreas in a manner additive with GLP-1 itself. These compounds may lead to the identification or design of orally active GLP-1 agonists.ago-allosteric modulator ͉ allosteric ͉ G protein-coupled receptor ͉ screening ͉ cAMP
Recently, the first basal oral insulin
(OI338) was shown to provide
similar treatment outcomes to insulin glargine in a phase 2a clinical
trial. Here, we report the engineering of a novel class of basal oral
insulin analogues of which OI338, 10, in this publication,
was successfully tested in the phase 2a clinical trial. We found that
the introduction of two insulin substitutions, A14E and B25H, was
needed to provide increased stability toward proteolysis. Ultralong
pharmacokinetic profiles were obtained by attaching an albumin-binding
side chain derived from octadecanedioic (C18) or icosanedioic acid
(C20) to the lysine in position B29. Crucial for obtaining the ultralong
PK profile was also a significant reduction of insulin receptor affinity.
Oral bioavailability in dogs indicated that C18-based analogues were
superior to C20-based analogues. These studies led to the identification
of the two clinical candidates OI338 and OI320 (10 and 24, respectively).
Optimization of a new series of small molecule human glucagon receptor (hGluR) antagonists is described. In the process of optimizing glucagon receptor antagonists, we counter-screened against the closely related human gastric inhibitory polypeptide receptor (hGIPR), and through structure activity analysis, we obtained compounds with low nanomolar affinities toward the hGluR, which were selective against the hGIPR and the human glucagon-like peptide-1 receptor (hGLP-1R). In the best cases, we obtained a >50 fold selectivity for the hGluR over the hGIPR and a >1000 fold selectivity over the hGLP-1R. A potent and selective glucagon receptor antagonist was demonstrated to inhibit glucagon-induced glycogenolysis in primary rat hepatocytes as well as to lower glucagon-induced hyperglycemia in Sprague-Dawley rats. Furthermore, the compound was shown to lower blood glucose in the ob/ob mouse after oral dosing.
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