Written by Dr Rajesh Kesari MD   
Tuesday, 08 December 2009 14:07

Insulin is a hormone secreted by the endocrine part of the organ pancreas.Pancreas in our body

Pancreas is located just below the Diaphragm near stomach. It has two main parts- the exocrine and the endocrine parts.

Exocrine Pancreas-Enzymes & juices

The exocrine pancreas secretes enzymes like amylase, lipase etc. into the intestines through a duct ( or pipe), these enzymes (chemicals substances) help in the breakdown of proteins and their subsequent digestion.

Endocrine Pancreas-Hormones

Insulin factoryThe other important part of the pancreas is the endocrine part- it consists of the islets of Langerhans ( named after Paul Langerhans who first described them in 1869) these are groups of cells which produce and secretes hormones directly into the blood circulation. About one million of these islets are scattered all over the pancreas of a healthy adult. By weight this part of pancreas constitutes 1-1.5 gms (hardly 1-2%) of the whole organ, but its functional importance is of tremendous value.

Beta Cells-Insulin factory

The Islets of Langerhans contain five different groups of cells each responsible for secretion of different hormones, namely Insulin, Glucagon, Somatostatin, Pancreatin, and Ghrelin Insulin is secreted by the Beta cells of the islets of Langerhans. It is released directly into the blood circulation by the beta cells. Insulin release is triggered by the rise of glucose levels in the blood flowing past the beta cells.


The Beta cells contain huge amount of insulin stored in the storage vesicles inside the cells, but the quantity of insulin which can be immediately released into the blood circulation is limited. Once released into the circulations insulin travels with blood to all the parts of the body. Cells which require insulin have insulin receptors (sort of antenna’s hanging out on their external walls). These are most abundant in Muscles, Liver, Adipose (fat) tissue, Kidneys, Nerve cells etc. Glucose is absorbed by these cells and either utilized immediately for providing energy or stored as glycogen (animal starch) or Fat as energy reserve or store which can be later on converted to glucose and utilized for generating energy. Insulin has many other effects in the body which make it of such a great importance, some of the prominent effects of insulin are: Glucose, energy metabolism Fat metabolism Protein synthesis, Growth stimulation In Type 1 Diabetes these types of cells are destroyed by the immune system of the body and the body is unable to produce any of its own insulin- hence arises the need for insulin injections. Whereas in Type 2 Diabetes, the action of Insulin on various tissues of the body is insufficient, this is also termed as insulin resistance; hence pancreas, more specifically Beta cells release more insulin into circulation to compensate for the inefficient insulin or insufficient action of insulin. Initially the pancreas may be able to compensate and keep the Blood glucose levels under control, but the other effects of insulin deposition of fat, damage to blood vessels, excessive protein synthesis have adverse effects and result in complications of Diabetes.

Last Updated on Thursday, 25 March 2010 07:52