I am updating my article on the usefulness of the SDMA kidney test.
If your vet  has followed SDMA levels in your pet, perhaps you would 
share those values with me. RSH email

This is my fanciful drawing and simplified explanation of how diabetes affects your cat.

Two compounds are involved, the Glucose molecule (drawn to the far upper left) and the much larger insulin molecule next to it. Both compounds circulate freely in your cat’s blood. The glucose came from the foods your cat ate or was produced in its liver from stored carbohydrates (glycogen) and proteins. The insulin molecules were produced in its pancreas.

Glucose is the primary energy source for the estimated 5-10 trillion cells that compose your cat’s body.

At the upper right is a fanciful image of one of those cells. Glucose molecules can not pass into these cells without the aid of insulin. And in Type II diabetes, insulin is less effective in allowing glucose to enter and the amount of it present may be reduced. Once inside the cells, the glucose is taken up by the cells many or single mitochondria (aka mitrochonrion), represented as oval yellow bodies with honeycomb compartments.

Your cat's mitochondria function as microscopic “power plants” generating the chemical energy all cells need - much of it by “burning: (oxidizing) glucose.

In the lower right of the illustration, I drew the cats liver and intestines, with the cat’s pinkish pancreas snuggled between loops of its small intestine. Within its pancreas are many small island, the islets of Langerhans. These are the portions of your cat’s pancreas that secrete insulin. The microscopic view of these island-areas that I drew, shows one with a normal functioning islet and another, to the left of it, in which the islet is no longer producing insulin due to the presence of amyloid.