Insulin glucagon, antagonistic effects

Glucagon, a peptide of 29 amino acids, is a product of the A cells of the pancreas. It is the antagonist of insulin and, like insulin, mainly influences carbohydrate and lipid metabolism. Its effects are each opposite to those of insulin. Glucagon mainly acts via the second messenger cAMP (see p. 384). 

Distinct antagonistic effects of glucagon and insulin in the Embden-Meyerhof-chain... 

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. 

Glucagon is considered to be the hormonal antagonist of insulin.29,35 The primary effect of glucagon is to increase blood glucose to maintain normal blood glucose levels and to prevent hypoglycemia.35,93 Glucagon pro-... 

Some clinicians believe that insulin or glucagon therapy for calcium channel antagonist poisoning should be used early in the course of therapy. Others reserve it for life-threatening symptoms not responsive to other therapy. More safety and effectiveness data are needed to define the place of these two agents in therapy. 

But if we infuse glucagon plus lactate simultaneously there is a sharp rise in the content of GBP and a decrease in the quantity of FDP, thereby augmenting the ratio G6P/FDP to more than 100 as a reflection of the flow reversal. - The following table shows once more the adjustment of the steady state of glucose-6-phosphate and fructosediphosphate under the effect of insulin. As is to be expected of an antagonist the effects of insulin are the exact opposite, i.e. with insulin the content of GBP falls and that of FDP rises the ratio of GBP/FDP is only 2. The effect of insulin also becomes particulary clear by simultaneous lactate infusion the GBP level no more rises. 

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