Glucagon function

Insulin and glucagon are produced in the pancreas by cells known as islets of Langerhans. P-Cells make up 70% to 90% of the islets and produce insulin, whereas P-cells produce glucagon. The main function of insulin is to decrease blood glucose levels, whereas glucagon, along with other counterregulatory... 

Discuss functions and factors regulating release of the following hormones thyroid hormones, calcitonin, parathyroid hormone, catecholamines, aldosterone, cortisol, adrenal androgens, insulin, and glucagon... 

Factors that stimulate glucagon secretion include a decrease in blood glucose an increase in blood amino acids sympathetic nervous stimulation stress and exercise. Factors that inhibit glucagon secretion include insulin and an increase in blood glucose. Table 10.2 summarizes the major functions of the hormones discussed in this chapter. 

Glucagon secreted in response to hypoglycemia and functioning via a membrane-associated receptor that increases cAMP concentration... 

The function of glucagon is to respond rapidly to an acute fall in the blood glucose level by stimulating glucose release by the liver and fatty acid release by adipose tissue. 

II.f.2.2. Sulphonylureas. These drugs stimulate pancreatic /3-cell insulin secretion, reduce serum glucagon levels, potentiate insulin action on target tissues, and improve /3-cell function. The sulphonylureas differ in their potency, extent of hepatic metabolism, hypoglycaemic activity of their metabolites, renal excretion, peak and duration of action, side effects and costs. 

The toxicity associated with propranolol is for the most part related to its primary pharmacological action, inhibition of the cardiac (3-adrenoceptors. This topic is discussed in detail in Chapter 11. In addition, propranolol exerts direct cardiac depressant effects that become manifest when the drug is administered rapidly by the IV route. Glucagon immediately reverses all cardiac depressant effects of propranolol, and its use is associated with a minimum of side effects. The inotropic agents amrinone (Inocor) and milrinone (Primacor) provide alternative means of augmenting cardiac contractile function in the presence of -adrenoceptor blockade (see Chapter 15). Propranolol may also stimulate bron-chospasm in patients with asthma. 

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