Insulin

Insulin (Latin insula, "island", as it is produced in the Islets of Langerhans in the pancreas) is a polypeptide hormone that regulates carbohydrate metabolism. Apart from being the primary effector in carbohydrate homeostasis, it also has a substantial effect on small vessel muscle tone, controls storage and release of fat (triglycerides) and cellular uptake of both amino acids and some electrolytes. In this last sense, it has anabolic properties. Its concentration (more or less, prsence or absence) has extremely widespread effects throughout the body.

The brain and hypoglycemia

Though other cells can use other fuels for a while (most prominently fatty acids), neurons are dependent on glucose as a source of energy in the non-starving human. They do not require insulin to absorb glucose, unlike muscle and adipose tissue and they have very small internal stores of glycogen. Thus, a sufficiently low glucose level first and most dramatically manifests itself in impaired functioning of the central nervous system – dizzness, speech problems, even loss of consciousness, are common. This phenomenon is known as hypoglycemia or, in cases producing unconsciousness, hypoglycemic coma (formerly termed insulin shock from the most common causative agent). Because endogenous causes of insulin excess (such as an insulinoma) are extremely rare naturally, the overwhelming majority of hypoglycemia cases are caused by human action (e.g. iatrogenic, caused by medicine), and are usually accidental. There have been a few cases reported of murder, attempted murder or suicide using insulin overdoses, but most insulin shock appears to be due to mismangement of insulin (didn't eat as much as anticipated, or exercised more than expected), or a mistake (e.g. 200 units of insulin instead of 20).

Related Topics:
Neurons - Central nervous system - Hypoglycemia - Hypoglycemic coma - Insulin shock - Insulinoma - Iatrogenic

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Causes of hypoglycemia are:

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• oral hypoglycemic agents (eg, any of the sulfonylureas, or similar drugs, which increase insulin release from beta cells in response to a particular blood glucose level)
• external insulin (usually injected subcutaneously)