Glucagon blood glucose

Storage and utilization of tissue glycogen, maintenance of blood glucose concentration, and other aspects of carbohydrate metabolism are meticulously regulated by hormones, including insulin, glucagon, epinephrine, and the glucocorticoids. 

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... 

When the actions of one hormone oppose the effects of another, the result is antagonism. For example, insulin decreases blood glucose and promotes the formation of fat. Glucagon, on the other hand, increases blood glucose and promotes the degradation of fat. Therefore, the effects of insulin and glucagon are antagonistic. 

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. 

In a person with glucose 6-phosphatase deficiency, ingestion of galactose or fructose causes no increase in blood glucose, nor does administration of glucagon or epinephrine. 

An underweight 4-year-old boy presents semi-comatose in the emergency room at 10 a.m. Plasma glucose, urea, and glutamine are abnormally low acetoacetate is elevated and lactate is normal. He Is admitted to the ICU, where an increase in blood glucose was achieved by controlled infusion of glucagon or alanine. Which metabolic pathway is most likely deficient in this child ... 

The role of glucagon and insulin in the regulation of glu-coneogenesis, along with other factors, is to maintain the blood glucose concentration in starvation. This is discussed in Chapter 12. 

Glucagon is secreted by the a-cells in the Islets of Langerhans in response to a decrease in the concentration of blood glucose. It binds to a receptor in liver and adipose tissue which activates adenyl cyclase and raises the innacel-lular level of cAMP, which activates protein kinase A (Figure 12.13). 

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. 

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