Question

Briefly explain the hormonal regulation of blood glucose level.

Answer 1

Hint: Blood sugar, or glucose, is the main sugar found in the bloodstream that is obtained from the food that we eat. It carries glucose to all the body cells to be used for energy. Regulation of blood glucose is mainly done through the endocrine hormones secreted in the pancreas.

Complete answer:
The significant regulation of blood glucose level is done by the following hormones of the pancreas:
1. Insulin
2. Glucagon
3. Somatostatin
4. Amylin.
Insulin (formed in the pancreatic beta cells) lowers the blood glucose levels, whereas glucagon (formed in the pancreatic alpha cells) elevates the blood glucose levels. Somatostatin is formed in the delta cells of the pancreas and assists in balancing insulin and glucagon. It helps the pancreas in turning on or turning off each of the opposing hormones, alternately. Amylin is a hormone, made in a 1:100 ratio with insulin that helps in increasing satisfaction and state of fullness from a meal and thereby prevents overeating. It also helps to slow down the contents of the stomach from emptying too quickly thereby avoiding a quick spike in the blood glucose levels.
Consuming a carbohydrate rich meal leads to the increase of blood glucose levels. The pancreas then turns on insulin production and turns off the glucagon production. Glucose from the bloodstream will enter liver cells and stimulate the action of several enzymes to convert the glucose to chains of glycogen as long as both insulin and glucose remain plentiful. The concentration of glucose in the bloodstream is determined by the balance between the rate of glucose entering and the rate of glucose leaving the circulation. These signals are delivered throughout the human body by two pancreatic hormones called insulin and glucagon.
Insulin is a peptide hormone made in the beta cells of the pancreas. After a meal, insulin is secreted into the bloodstream and when it reaches the insulin-sensitive cells, i.e., liver cells, fat cells and striated muscle, insulin will stimulate them to take up glucose and metabolize it. Insulin synthesis and its release from the beta cells is stimulated by the rising concentrations of blood glucose.
Glucagon is a peptide hormone which is secreted by the pancreas to raise blood glucose levels. Thus, its effect is opposite to the effect of insulin. When it reaches the liver, glucagon converts stored glycogen into glucose through a process called glycolysis. This glucose is then released into the bloodstream. High amounts of glucose in the bloodstream initiates the release of insulin which takes up the glucose in the blood and delivers it to the insulin dependent tissues, such as muscle cells. Thus glucagon and insulin work together automatically as a negative feedback system to keep the blood glucose levels stable.
Amylin is a peptide hormone secreted along with insulin from the beta cells of the pancreas in a 1:100 ratio. It inhibits the secretion of glucagon and thus helps lowering the blood glucose levels. It also delays gastric emptying after a meal and increases brain satiety to help feel full after a meal.
Somatostatin is produced in the delta cells of the pancreas and inhibits the secretion of other pancreatic hormones such as insulin and glucagon. The hormone is also produced in the gastrointestinal tract where it reduces gastric secretion, gastrointestinal motility and inhibits the secretion of gastrointestinal hormones, including gastrin and secretin.

Note:
High blood glucose levels are called 'hyperglycemia'. Blood glucose is considered "high" when it is 160 mg/dl or above the individual’s blood glucose target. Blood glucose level at 50 mg/dl or under is considered dangerously low and the condition is called ‘hypoglycemia’.