Disorders of glucose metabolism in uremia

Chronic renal failure results in a variety of metabolic derangements that perturb glucose homeostasis. These may in part result from the fact that the kidney plays a prominent role in the metabolism of insulin as well as a number of other low-molecular-weight peptide hormones that affect carbohydrate metabolism. Specific abnormalities in glucose utilization that appear to be related to alterations in membrane receptors, resulting in increased glucagon sensitivity and decreased insulin action, are a newly recognized factor in intolerance to oral glucose. Glucose production and utilization are both abnormally increased in patients with chronic uremia, and these disturbances are only partially corrected by hemodialysis treatment. The mechanism(s) contributing to these changes is unclear, but seems to involve a combination of humoral and cellular factors. These include some degree of insulin resistance, probably inadequately modulated proteolytic responses to glucagon and parathyroid hormone, and a basic defect in energy production that alters intracellular concentrations of high-energy phosphate-containing nucleotides. It is unclear whether these changes in carbohydrate tolerance pose an increased risk for the premature development of cardiovascular disease in patients with renal failure, as they appear to do in the nonuremic population. The occasional patient with renal failure may develop clinical hypoglycemia when glucose utilization continues in a setting in which the hepatic capacity to produce glucose is reduced, probably as a consequence of altered substrate delivery and/or inhibition of one or more key gluconeogenic enzymes.