Insulin: There Is more To It Then Just Glucose

Insulin is a hormone produced by the human body generally known for its effects on blood glucose and its ability to bring glucose molecules into the cells of the body where it is used as a form of raw fuel or “Crude Oil”. Once inside the cell, glucose gets transformed into consumption fuel in the cell “refineries” also known as mitochondria.  The refined end product is the gasoline of the cell (Adenosine Tri-Phosphate).

Insulin, however, has also other important properties and roles that make it an essential life sustaining hormone such as in protein synthesis, the regulation of body electrolyte balance and in fat storage.

Insulin and Proteins

Insulin molecules facilitate the uptake of amino acids from blood into skeletal muscle cells to maintain and build muscle proteins. This uptake takes place on the borders of each cell via sophisticated transportation vehicles and is among other things enhanced by the electric charge or electric potential energy on the cell border (cell membrane) itself.

Insulin also helps the uptake of amino acids by liver cells. The liver as an organ uses amino acids as core elements in the building of plasma proteins such as lipoproteins, albumin, clotting factors as well as numerous enzymes that play a key role in the functions of the liver as a body detoxification and elimination facility.

Amino acid uptake in almost all tissues of the body including vital organs such the brain, heart and kidneys, although to a much lesser extent than in the skeletal musculature and liver, is assisted by insulin.

Insulin and Electrolytes

Insulin plays a key role in regulating body potassium and many other electrolytes including sodium and magnesium. It assists cells in taking up potassium molecules, through specialized transport vehicles in the cell borders (membranes). Potassium, magnesium, sodium and other electrolytes are essential in sustaining each cell thanks to the electric potential that they maintain and regulate. They are crucial for the generation and transmission of nerve impulses as well as muscle contractions. This electric potential on cellular membranes can be philosophically viewed by some as a marvel of nature or divine spark, while others may see it through a purely scientific lens. Either way, it is a fundamental aspect (and insulin plays a crucial role in it) and can be a subject for many philosophical discussions about the complexity and interconnectivity of living organisms.  

Insulin and Fats

Fats, just like amino acids and electrolytes, are ingested by humans and are subject to major influence by insulin as to how they are used by the body. As fats are ingested and digested in the gastrointestinal tract, they are absorbed in the circulation and flow through it as small lumps of fat called Chylomicrons. These particles are in fact transportation vehicles for triglyceride loads which then distribute their load to fat tissues, skeletal and heart muscles. For the off-loading of fats to take place efficiently, the inner lining of the blood vessels in fat tissues and muscles has an enzyme that can cleave/unpack packaged triglycerides into free fatty acids. It is this enzyme that is directly influenced and kept active by insulin and leads to making free fatty acids available for uptake by muscle and fat cells. Once taken up, the fatty acids are subsequently used by muscle tissues as crude oil/fuel. This crude oil is then “refined” into cellular gasoline (ATP) for direct use by muscle cells. In fat tissues this happens as well, however to a lesser extent because fatty acids are primarily stored in depot form inside fat cells. These can then be mobilized later as reserve fuel if the need arises. It is useful to know that when there is insufficient or lacking insulin in the body, triglycerides tend to go up significantly and are one of the key hallmarks of patients who need insulin therapy.  

It is of no surprise that a phrase by the influential author William Francis Ganong carries great meaning. This quote poetically captures the state of diabetes mellitus with the following words: “Diabetes is starvation in the midst of plenty”. Despite an abundant presence of glucose, amino acids and fats in the circulation, the cells of the body are in fact being “starved” because an absence of insulin, or its inability to perform its function as is the case in insulin resistance, renders those abundantly present nutrients useless.