Identify an antagonistic pair of hormones and describe their action.

Answer 1

The pancreas is a prime example of an organ that employs antagonistic hormones. When the blood sugar level is too high, the pancreas releases insulin to promote the conversion of glucose in the blood to glycogen to be stored in the liver. Because the sugar is now being stored in the liver, and is no longer in the blood, the blood-sugar level decreases. When the blood sugar level is too low, the pancreas releases glucagon to stimulate the conversion of glycogen back to glucose and released back into the blood. This raises the blood sugar level.

Another example is that of calcitonin (released by the parafollicular cells of the thyroid gland) and parathyroid hormone (released by chief cells of the parathyroid glands). When blood calcium levels are too high, calcitonin is released to inhibit osteoclasts from breaking down bone and releasing calcium. When blood calcium levels are too low, parathyroid hormone is released to promote calcium absorption in the intestines and calcium REabsorption in the distal convoluted tubules of the kidney.