Glucagon DuoSet ELISA, 5 plate

In normal metabolism, Glucagon is secreted in response to low blood glucose (hypoglycemia) and downregulated in response to high blood glucose (hyperglycemia). Although Glucagon binding sites are found in liver, brain, pancreas, kidney, intestine, and adipose tissue, the main activity of Glucagon receptors occurs in the liver, where Glucagon stimulates gluconeogenesis and glycogenolysis, thereby increasing blood glucose (1-4). It is particularly important that the brain receive sufficient glucose, since it is unable to store more than a minute quantity. Therefore the release of Glucagon from alpha -cells is under control by both hormones and neurotransmitters, and is very responsive to circulating glucose concentration. Insulin, and/or the zinc that islet beta cells secrete with it, downregulates Glucagon secretion in intact islets (5, 6). Glucagon secretion is also downregulated by the neurotransmitter gamma -aminobutyric acid (GABA), somatostatin produced by islet δ-cells, and GLP-1, but is enhanced by the neurotransmitter L-glutamate, amino acids (especially arginine), and Glucagon itself (2-4, 7). Through receptors on the alpha -cells, these substances affect potassium, sodium, and calcium channel activity and alter intracellular calcium concentration (2-4). Glucose suppression of Glucagon secretion is probably indirect, acting through paracrine signals from other islet cells (8).