Function of Endocrine Organs in Hemodialyzed Patients of Long-Term Erythropoietin Therapy

Abstract: Endocrine abnormalities in patients with chronic renal failure are well documented. The present study aimed to assess the influence of long-term erythropoietin (EPO) therapy on endocrine abnormalities in hemodialyzed patients. Two groups of hemodialyzed patients, each of which comprised 17 subjects, were examined. The first group was treated by EPO (EPO group) while the second one did not receive this hormone (No-EPO group). A complete biochemical and hormonal check-up was performed before and at the 3, 6, 9, and 12 month points of the study period. Normal values for the estimated parameters were obtained in appropriately selected sex- and age-matched healthy subjects. After EPO therapy, an increase of the hematocrit value from 21.8 ± 0.9 to 32.6 ± 0.9% was observed, which was accompanied by a significant decline of plasma ferritin and saturation of transferrin. In patients of the No-EPO group, a significant although less marked rise of the hematocrit value (21.4 ± 0.4 to 24.2 ± 0.6%) was also noticed. EPO therapy did not change plasma levels of electrolytes (Na, K, Ca, inorganic phosphate), osteocalcin, creatinine, glucose, and alkaline phosphatase as well as plasma concentrations of calcium-related hormones (PTH, calcitonin, 1,25OH]₂D₃), vasopressin, and triiodothyronine. EPO treatment induced a significant decrease in somatotropin, prolactin, follitropin, lutropin, ACTH, cortisol, plasma renin activity, aldosterone, noradrenaline, adrenaline, dopamine, glucagon, pancreatic polypeptide, and gastrin plasma levels and an increase in plasma insulin, estradiol, testosterone, atrial natriuretic peptide, thyrotropin, and thyroxine. These EPO-induced endocrine alterations were restricted mostly to the first 6 months of EPO administration. In patients of the No-EPO group, a significant decrease in the plasma levels of prolactin, noradrenaline, and dopamine and an increase of estradiol plasma levels were also noticed during the 1-year study period. Therefore, long-term treatment by EPO shows profound effects on the function of several endocrine organs. These effects are transitory and predominantly restricted to the first 6 months of EPO therapy. Not all endocrine alterations observed in EPO-treated patients seem to be due to the administration of this hormone.