Exendin-4 Acetate (Exenatide acetate), a 39 amino acid peptide, is a long-acting glucagon-like peptide-1 receptor agonist with an IC50 of 3.22 nM.
In human umbilical vein endothelial cells, Exendin-4 significantly increases NO production, endothelial NO synthase (eNOS) phosphorylation, and GTP cyclohydrolase 1 (GTPCH1) level in a dose-dependent manner[2]. Exendin-4 shows cytotoxic effects to MCF-7 breast cancer cells with IC50 of 5 μM at 48 hour[3].
Both low- and high-dose Exendin-4 treatment in ob/ob mice improve serum ALT and reduce serum glucose, and calculated HOMA scores compared with control. Exendin-4-treated ob/ob mice sustain a marked reduction in the net weight gain in the final 4 weeks of the study period[4]. Animals treated with Exendin-4 have more pancreatic acinar inflammation, more pyknotic nuclei and weigh significantly less than control rats. Exendin-4 treatment is associated with lower leptin levels as well as lower HOMA values in rats[5]. Exenatide causes dose-dependent relaxation of rat thoracic aorta, which is evoked via the GLP-1 receptor and is mediated mainly by H2S but also by NO and CO[6].
References:
[1]. Doyle ME, et al. The importance of the nine-amino acid C-terminal sequence of exendin-4 for binding to the GLP-1 receptor and for biological activity. Regul Pept. 2003 Jul 15;114(2-3):153-8.
[2]. Wei R, et al. Exenatide exerts direct protective effects on endothelial cells through the AMPK/Akt/eNOS pathway in a GLP-1 receptor-dependent manner. Am J Physiol Endocrinol Metab. 2016 Jun 1;310(11):E947-57.
[3]. Fidan-YaylalI G, et al. Antidiabetic exendin-4 activates apoptotic pathway and inhibits growth of breast cancer cells. Tumour Biol. 2016 Feb;37(2):2647-53.
[4]. Ding X, et al. Exendin-4, a glucagon-like protein-1 (GLP-1) receptor agonist, reverses hepatic steatosis in ob/obmice. Hepatology. 2006 Jan;43(1):173-81.
[5]. Nachnani JS, et al. Biochemical and histological effects of exendin-4 (exenatide) on the rat pancreas. Diabetologia. 2010 Jan;53(1):153-9.
[6]. Sélley E, et al. Exenatide induces aortic vasodilation increasing hydrogen sulphide, carbon monoxide and nitric oxide production. Cardiovasc Diabetol. 2014 Apr 2;13:69.