Suppresses insulin secretion (in cats)
According to Dr. E. Hodgkins and also Dr. J. Rand[3][4], hyperglycemia also suppresses insulin secretion from the beta cells. After just 3 to 7 days at 30mmol/L (540 mg/dL), Dr. Rand found only "minimal" insulin secretion from the beta cells. Combined with the insulin resistance, this means that once a cat becomes diabetic, it will tend to remain that way until treated with exogenous insulin.
Raises insulin requirements
Glucose toxicity can continue to raise insulin requirements for some time, even after the "glass floor" is broken and blood glucose is brought under control. This effect may take a long time (weeks) to wear off, due to the gradual healing of formerly glucose-damaged tissue.
As the damage from glucose toxicity is repaired, the tissues will heal; the process can take 1-12 weeks[5]. However, healing can take place only when blood glucose & fatty acid concentrations are reduced.