What is the mechanism of the following adverse effects of beta-2 selective agonists (hyperglycemia, hypokalaemia and tremors)?
The elevated blood glucose is due to stimulation of beta-2 receptors in the liver which induces glycogenolysis with release of glucose from the liver. The hypokalemia is due to stimulation of insulin secretion by the elevated blood glucose; insulin stimulates entry of glucose and potassium into the cells. Tremors may be related to stimulation of glycogenolysis in the muscle (unlike the liver; glycogenolysis in the muscle does not release glucose to the blood but lactate is that released because the glucose is utilized locally for muscle contraction).
