Long-term effects of nifedipine on carbohydrate and lipid metabolism in hypertensive hemodialyzed patients

Cardiac disease in chronic uremia: management

Heart disease is a common cause of morbidity in end-stage renal disease (ESRD) patients. The management of heart disease in these patients requires a multidimensional approach to the management of heart failure, coronary disease, and arrhythmias, and to risk factors such as hypertension, anemia, secondary hyperparathyroidism, and electrolyte/acid-base disturbances. Coronary artery disease management includes use of antianginal drugs and revascularization of coronary arteries with angioplasty +/- stent placement or coronary artery bypass grafting. The long-term outcomes of these procedures need to be assessed and improved. Hypertension occupies a major role in the pathogenesis of heart disease in ESRD, and early and adequate control of hypertension is likely to have a major impact on the progression of cardiac disease. This entails the achievement of optimal volume status, combined with the appropriate use of antihypertensive agents such as calcium channel blockers, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, vasodilators, alpha-blockers, and central sympatholytic drugs. In ESRD patients, specific dialysis-related complications such as intradialytic hypotension and pericardial effusion may have additional effects on cardiac function and require attention. The choice of dialysate composition and membrane may influence clinical outcomes with specific effects on cardiac performance.

Correction of glucose intolerance and the impaired insulin release of chronic renal failure by verapamil

Insulin release from pancreatic islets is impaired in chronic renal failure (CRF), and this is due to the state of secondary hyperparathyroidism of CRF. This defect in association with resistance to the peripheral action of insulin-caused glucose intolerance in CRF. It has been suggested that the impaired insulin release induced by excess parathyroid hormone (PTH) is related to the ability of the hormone to augment calcium entry into the pancreatic islets, resulting in accumulation of calcium in the pancreas. Therefore, a calcium channel blocker may antagonize this effect of PTH, and hence normalize glucose tolerance in CRF. The present study examined this postulate by studying intravenous glucose tolerance and insulin release from pancreatic islets in normal and CRF rats and in CRF animals treated with the calcium channel blocker, verapamil. Rats with 42 days of CRF displayed impaired glucose tolerance, significant reduction (P less than 0.01) in insulin release by islets, and doubling of calcium content of the pancreas (P less than 0.01) as compared to normal rats. Simultaneous treatment of CRF rats with verapamil for 42 days resulted in normal glucose tolerance, higher blood insulin levels during glucose infusion, normal calcium content of the pancreas, and normal insulin secretion by the islets. Treatment of normal rats with verapamil for 42 days did not affect any of the parameters studied. The results show that the calcium channel blocker, verapamil, by preventing calcium accumulation in the pancreas, reversed the abnormalities in insulin release that occur in CRF. This effect allowed a greater rise in blood levels of insulin during glucose infusion in CRF rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of nifedipine on carbohydrate metabolism in the rat

The potential role of an oral administration of nifedipine was investigated in the rat. Therefore, animals were fed on a nifedipine-containing or control diet for 12 days. Nifedipine caused a significant decrease of liver glycogen (47.9 +/- 4.9 vs 132.6 +/- 17.1 micrograms/mg protein), whereas liver glucose (213.1 +/- 15.3 vs 110.4 +/- 6.4 micrograms/mg) and lactate (44.8 +/- 4.1 vs 26.5 +/- 1.8 nmol/mg) concentrations increased. Various concentrations of nifedipine failed to influence glycogenolysis but stimulated gluconeogenesis in isolated rat hepatocytes. Blood lactate and pyruvate levels were significantly elevated in the nifedipine pretreated rats, whereas ketone bodies remained constant. Nifedipine pretreatment also increased the rates of excretion of various electrolytes and water followed by significantly lower plasma sodium, potassium, phosphate, and normal glucose values. We conclude that nifedipine-induced liver glycogenolysis may deteriorate glucose tolerance in patients with an already impaired carbohydrate metabolism.