Hormonal Regulation of Blood Glucose Level

Concentration of glucose in blood is critical factor for normal human physiology.

Maintenance of blood glucose level is essential for body energy need and normal activity of body organs.

There are several hormones in body which are responsible for maintaining / regulating the blood glucose level and secreted from different organs.

Hormones Responsible for Blood Glucose Regulation

Organ	Hormone Secreted
Pancreas	Glucagon (α-cells) Insulin (β-cells) Somatostatin (δ-cells)
Adrenal Medulla	Epinephrine
Adrenal Cortex	Cortisol
Thyroid	Thyroxine
Pituitary Gland	Adrenocorticotropic Hormone (ACTH)

Effect of Hormones on Blood Glucose

Hormone that lowers blood glucose	Hormone that increases blood glucose
Insulin	Glucagon
Somatostatin	Cortisol
	ACTH
	Thyroxine

Insulin

Insulin is peptide hormone, produced by beta cells in the islets of Langerhans in pancreas.

Insulin regulates the metabolism of carbohydrates and fats by promoting the absorption of glucose from the blood to skeletal muscles and fat tissues.

There are receptors on cell surface, which are activated after insulin binding. This binding activates GLUT4 glucose transporter molecules, which carries glucose from cell membrane to inside the cell.

Insulin gets released when blood glucose level gets increase or glucose concentration inside cell is decreased for energy production.

Glucagon

Glucagon is produced by α cells of pancreas to maintain blood glucose level. Glucagon increases the blood glucose level.

It increases blood glucose level by:

• It stimulates the conversion of stored glycogen to glucose, which is released into blood stream.
• Glucagon promotes the formation of glucose from amino acids (Gluconeogenesis)
• It reduces glucose consumption from liver, so that glucose level become higher in blood.

Glucagon and insulin work together to maintain normal glucose levels.

Epinephrine

Brain sends signals to adrenal glands to release epinephrine through sympathetic response.

Epinephrine travel through blood stream and cause the liver to release glucose. This hormone also promotes breakdown of fats into glucose.

Cortisol

It is an steroid hormone, also secreted from adrenal gland.

It makes fat storage cells (adipose tissue) and muscle cell resistant to insulin.

So these cells cant stimulates by insulin which further no absorption of glucose from blood.

Cortisol also enhances the production of glucose from liver.

Thyroxine

Throxine hormone causes increased glucose production in the liver, rapid absrtion of glucose through intestine and increased insulin resistance, which leads to raise the glucose in the blood.

Adrenocorticotropic Hormone (ACTH)

The interior pituitary gland secretes growth hormone and ACTH. ACTH decreases glucose utilization and decrease glucose absorption.