Patients undergoing regular hemodialysis treatment display elevated intracellular free calcium and impaired glucose uptake in polymorphonuclear leukocytes (PMNLs) in the presence of enhanced serum parathyroid hormone (PTH) levels. Normalization of intracellular calcium can be achieved by different therapeutic interventions acting by different mechanisms. Effective oral 1,25-dihydroxyvitamin D3 therapy (0.5-1.0 microgram/day) normalizes PMNL cytosolic calcium via suppression of PTH levels. Hemodialysis patients treated orally with the calcium channel blocker nitrendipine (20-40 mg/day) normalizes calcium without affecting serum PTH levels. Both therapeutic interventions improved glucose uptake and displayed no synergistic effect.