Hyperglycemia or high blood sugar is a condition in which excess amount of glucose in the blood. The hyperglycemic hormone or glucagon is secreted by the alpha cells of the islets of Langerhans, that stimulates the release of glucose into the blood. Glucagon works antagonist of insulin. so glucagon is considered as hyperglycemic hormone.
Hypoglycemia or low blood sugar is a condition that occurs when level of blood sugar decreases to below normal level. Insulin is the major actor in causing hypoglycemia. There are many other hormones that modulate the release of insulin. For example, the incretin effect is the increase in insulin secretion caused by oral administration of glucose through the release of GLP-1 (glucagon like peptide) and GIP (gastric inhibitory peptide). These signals act to increase insulin secretion by the pancreas.