Insulin

[pgrmdave]

Does anybody know exactly how insulin works? I know it's necessary for the body to use glucose, but how does it work?

[InfiniteNow]

That's a great question. I've used the stuff for years and I'm not too sure. My limited understanding is that it's an enzyme which interacts with the food molecules in such a way so as to make the glucose attach to the hemoglobin... I'm curious now too.

 

Aha! Wiki...

 

http://en.wikipedia.org/wiki/Insulin#Actions_on_cellular_and_metabolic_level

 

The actions of insulin on the global human metabolism level include:

 

Control of cellular intake of certain substances, most prominently glucose in muscle and adipose tissue (about 2/3 of body cells).

 

Increase of DNA replication and protein synthesis via control of amino acid uptake.

 

Modification of the activity of numerous enzymes (allosteric effect).

 

 

The actions of insulin on cells include:

 

Increased glycogen synthesis – insulin forces storage of glucose in liver (and muscle) cells in the form of glycogen; lowered levels of insulin cause liver cells to convert glycogen to glucose and excrete it into the blood. This is the clinical action of insulin which is directly useful in reducing high blood glucose levels as in diabetes.

 

Increased fatty acid synthesis – insulin forces fat cells to take in blood lipids which are converted to triglycerides; lack of insulin causes the reverse.

 

Increased esterification of fatty acids – forces adipose tissue to make fats (ie, triglycerides) from fatty acid esters; lack of insulin causes the reverse.

Decreased proteinolysis – forces reduction of protein degradation; lack of insulin increases protein degradation.

 

Decreased lipolysis – forces reduction in conversion of fat cell lipid stores into blood fatty acids; lack of insulin causes the reverse.

Decreased gluconeogenesis – decreases production of glucose from various substrates in liver; lack of insulin causes glucose production from assorted substrates in the liver and elsewhere.

 

Increased amino acid uptake – forces cells to absorb circulating amino acids; lack of insulin inhibits absorption.

 

Increased potassium uptake – forces cells to absorb serum potassium; lack of insulin inhibits absorption.

 

Arterial muscle tone – forces arterial wall muscle to relax, increasing blood flow, especially in micro arteries; lack of insulin reduces flow by allowing these muscles to contract.

[CraigD]

Does anybody know exactly how insulin works? I know it's necessary for the body to use glucose, but how does it work?

As a reading of the preceding wiki link reveals, the metabolic action of insulin, and the molecule itself, is complicated. Though I wouldn’t claim that anybody knows exactly how it works, it’s one of the most studied hormones.

 

It helps, I think, to note that insulin is just one of many hormones, which all work in a similar way, binding with receptors on cell membranes to regulate membrane permeability and various cell processes. Insulin is a particularly important one, because of the importance of glucose metabolism, of which it’s the primary regulator.

 

Hormones and immune system cells are so similar that they can really be thought of as members of a common superclass. The distinction between them is mostly a functional one – more what sort of cell activities they control, than how they control them.