Around 80% of glucose uptake is insulin independent. That’s quite a lot. If you’re inclined to reject this study based on its age, consider the glucose clamp technique they’ve used: developed in 1979, it is still the gold standard today. 5 this means that it has been known for more than 30 years that there is considerable glucose uptake without insulin. Why then do medical schools teach students that insulin is an absolute requirement for glucose uptake?
Some think that without insulin, glucose just piles up outside the cell, causing high blood sugar and leaving the cell lacking glucose. In fact, during hyperglycemia, there is more glucose inside the cell than during normoglycemia. Again, from the 2001 review:
Contrary to most textbooks and previous teaching, glucose uptake is therefore actually increased in uncontrolled diabetes and decreased by insulin administration! The explanation for this is that because, even in the face of insulin deficiency, there are plenty of glucose transporters in the cell membranes. The factor determining glucose uptake under these conditions is the concentration gradient across the cell membrane; this is highest in uncontrolled diabetes and falls as insulin lowers blood glucose concentration primarily (at physiological insulin concentrations) through reducing hepatic glucose production.
The liver is the main reason that blood sugars rise and insulin lowers blood sugar by telling the liver to stop releasing sugar into the blood....read more>>>...
