Sustained negative feedback between haematocrit and serum erythropoietin concentration in end-stage renal failure

In a longitudinal study the individual values of serum erythropoietin (SEp) in end-stage renal failure were investigated in 15 patients. SEp was determined by use of the foetal mouse liver cell assay on three occasions: (A) 2--6 months before the onset of RDT, (B) on day of first dialysis, and (C) 2--6 months following the onset of RDT. In every patient SEp increased from (A) to (B), and decreased again from (B) to (C). Changes of haematocrit were exactly opposite to changes of SEp. The results demonstrate that even in the terminal stage of chronic renal failure erythropoietin production is stimulated or suppressed in response to variations in the degree of anaemia.