70).GLUCAGON

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a) is released by pancreatic islet cells
b) prevents insulin release
c) is raised following 24 hours of starvation
d) increases free fatty acid levels
e) is a positive inotrope

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Glucagon is secreted by the A cells of the pancreatic islets. It causes glycogen breakdown and release of glucose. It also increases hepatic glucose formation from amino acids, and breakdown of fats to form ketone bodies. Stimulates secretion of growth hormone, insulin and somatostatin. Its secretion is increased by beta-adrenergic stimulation, stress, exercise, amino acids, gastrin and starvation. Secretion is decreased by hyperglycaemia, somatostatin, ketone bodies, fatty acids, insulin, and alpha-adrenergic stimulation. In the heart, glucagon increases calcium transport into myocardial cells via adenylate cyclase activation.