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How does insulin change in type 2 diabetes?

Describes the key changes that happen in insulin secretion and action of insulin in type 2 diabetes
© University of Southampton

Type 2 diabetes occurs predominately in adults and is typically associated with obesity and inactivity.

Insulin resistance

Initially, the body is insulin resistant – this means that even though the pancreas is producing insulin, the cells in the body do not respond to it normally.

It is not totally understood why this happens but it may be due to defective cellular pathways including binding of insulin to its receptor where it triggers its actions, dysfunctional signals sent from receptor binding, or due to overeating, the insulin receptors are all fully bound with insulin and so insulin can have no additional effects as there are no spare insulin receptors.

Insulin resistance through malfunctioning insulin receptor site. Figure: insulin resistance through malfunctioning insulin receptor site

How insulin resistance affects the organs

Insulin resistance affects many of the organs in the body, including liver, muscle and adipose tissue that are important for regulation of glucose homeostasis.

Insulin resistance also affects other organs such as the ovaries (polycystic ovary syndrome) and the blood vessels (contributing to heart disease, and vascular diseases such as stroke and peripheral vascular disease).

Did you know? Some people with type 2 diabetes do not ever need insulin treatment but require medicines that make their cells respond better to insulin. For further information on medications for type 2 diabetes, see the Diabetes UK section on tablets and medication.

Why some people require treatment with insulin

In many people with type 2 diabetes, the β cells work extra hard to produce more insulin to try to overcome the insulin resistance. This leads to exhaustion of the β cells and their destruction, and a reduction in the amount of insulin produced.
This is why some people with type 2 diabetes require treatment with insulin. Even if they need insulin, they still have type 2 diabetes and not type 1 diabetes.
Did you know? In type 2 diabetes, the time at which insulin treatment is needed varies between different people. That said, some people with type 2 diabetes may never require insulin treatment, but use other therapies instead.
© University of Southampton
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Understanding Insulin

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