Glucagon, a hormone secreted by the alpha cells of the islets of Langerhans when blood glucose concentration falls, has several functions that are diametrically opposed to those of insulin.
The most important function of glucagon is to increase the blood glucose concentration, an effect that is exactly the opposite that of insulin.
- first is true, second is fale
- first is false, second is true
- both are true
- both are false
Both are true, Glucagon is the primary "counterregulatory" hormone that increases blood glucose levels through its effects on the liver glucose output.
Glucagon release by alpha cells (in islets of Langerhans of pancreas) is promoted by: 1. Fall in blood glucose level (hypoglycemia) THIS IS THE MOST POTENT FACTOR 2. Sympathetic stimulation 3. increased level of amino acids ARGININE AND ALANINE in blood plasma (in this case glucagon and insulin act the same) 4. circulating catecholamines via beta2 adrenergic receptors.
Factors that decrease glucagon: Rise in blood glucose level, insulin, free fatty acids, ketoacids and Somatostatin (aka, growth hormone inhibitory hormone, which also depresses insulin.)