Hormone

1. Hormones are organic substance secreted by plants and animals that functions in the regulation of physiological activities and in maintaining homeostasis.
2. Hormones carry out their functions by evoking responses from specific organs or tissues that are adapted to react to minute quantities of them.

Insulin

1. Insulin is a hormone that regulates the level of sugar (glucose) in the blood and is produced in the pancreas.
2. Insulin is secreted when the level of blood glucose rises after a meal.
3. When the level of blood glucose falls, secretion of insulin stops, and the liver releases glucose into the blood.
4. Inadequate production of insulin is responsible for the condition called diabetes mellitus.
5. Severe diabetics require periodic injections of insulin, which is extracted from the pancreas of pigs, sheep, and oxen.