Glucagon-like peptide-1 (GLP-1) is a 31 amino acid peptide hormone derived from selective cleavage of the proglucagon gene. It is mainly produced from enteroendocrine L-cells in GI tract. The other cleavage products derived from proglucagon genes are glucagon, GLP-2 and other small fragment peptides including Glicentin, Oxyntomodulin and two intervening peptides (IP-1 and IP-2). Except for glucagon cleaved in alpha cells of the pancreas, all other cleaved peptides occurred in enteroendocrine L cells of intestine.

GLP-1 has shown important roles in regulating glucose metabolic functions in humans. There are studies showing that GLP-1 is a potent anti-hyperglycemic hormone inducing glucose-dependent stimulation of insulin secretion while suppressing glucagon secretion. This dual control of insulin and glucagon has the benefit that the plasma glucose concentration is kept in the normal fasting range to avoid hypoglycemia caused by overstimulation of insulin. In addition, GLP-1 was reported to restore the glucose sensitivity of pancreatic beta cells, probably via the upregualtion of GLUT2 and glucokinase. GLP-1 was reported to inhibit pancreatic beta-cell apoptosis and stimulate the proliferation and differentiation of insulin-secreting beta-cells.

GLP-1 has shown potential clinical application as a biomarker and treatment option for Diabetes Mellitus, which is based on the following physiological functions mediated by GLP-1.

• Regulating insulin secretion by increasing insulin secretion from the pancreas in a glucose-dependent manner and increasing insulin-sensitivity in both alpha and beta cells
• Regulating glucagon secretion by decreasing glucagon secretion from the pancreas by engagement of a specific G protein-coupled receptor.
• Regulating food intake by inhibiting acid secretion and gastric emptying in the stomach and decreasing food intake by increasing satiety in brain.

Standard, Biotinylated GLP-1 peptide, and Positive Control should be stored at -20°C after arrival. Avoid multiple freeze-thaws. The remaining kit components may be stored at 4°C. Opened Microplate Wells and antibody (Item N) may be stored for up to 1 month at 2° to 8°C. Return unused wells to the pouch containing desiccant pack and reseal along entire edge.