What exactly is insulin resistance? One of insulin’s jobs is to help move glucose from the blood into the cells for energy. When blood glucose remains elevated despite normal or high levels of insulin, this is called insulin resistance. The cells are resisting insulin’s pleas to take up glucose. But why is this happening? What causes insulin resistance?
The current paradigm of understanding insulin resistance is the ‘lock and key’ model. The hormone insulin acts upon a cell surface receptor to do its job. The insulin receptor is like a lock keeping the gates to the cell closed. Insulin is like the proper key. When inserted, the gate opens to let glucose from the blood inside the cell for energy. Once you remove the key (insulin), the gate closes back up and blood glucose can no longer enter the cell.
During the phenomenon of insulin resistance, we imagine that the lock and key no longer fit together very well. The key (insulin) only partially opens the lock (receptor) and not very easily. Glucose cannot pass through the gate normally, and as a result, less gets into the cell. The blood glucose piles up outside the gate, becoming detectable as the clinical diagnosis of type 2 diabetes is made.