A 5-year-old boy with IDDM on a single morning dose of insulin has begun to have nightly enuresis. His FBS level generally is 200-250 mg/dl, and his blood glucose level before supper generally is 75-150 mg/dl. Most likely cause of this patient's enuresis is
Glycosuria from under-insulinization overnight Stress of chronic disease Urinary tract infection Somogayi phenomenon