Effect of long-term administration of recombinant human growth hormone (rhGH) on plasma erythropoietin (EPO) and haemoglobin levels in anaemic patients with adult GH deficiency

OBJECTIVE: We investigated the effect of recombinant human GH (rhGH) on erythropoietin (EPO) and haemoglobin (Hb) concentrations in anaemic patients with adult GH deficiency. PATIENTS AND DESIGN: rhGH was administrated in 8 patients with adult GH deficiency, three males and five females, aged from 24 to 69 years, mean (+/- SD) of 48.8 +/- 16.4 years, for 1 year by means of continuous subcutaneous infusion (CSI) at a flow rate of 0.036 U/kg/day using a portable syringe pump. Blood samples were obtained in the morning after an overnight fast every week for 1 month, followed by each month before and after the start of rhGH administration. RESULTS: Mean (+/- SE) plasma GH levels increased from 0.24 +/- 0.09 microg/l to 2.32 +/- 0.23 microg/l 1 week after the start of rhGH administration to maintain a steady state. Plasma IGF-I levels increased from 70.1 +/- 13.8 microg/l to 282.8 +/- 70.6 microg/l 1 week after the start of rhGH administration to maintain the steady state. Plasma EPO levels increased from 25.9 +/- 2.6 IU/l to 37.6 +/- 4.2 IU/l and 34.3 +/- 3.6 IU/l at 1 week and 2 weeks after the start of rhGH administration, respectively, and then decreased gradually to 14-9 +/- 2.1 IU/l at 10 months after the start of rhGH administration. Reticulocyte counts increased from 0.88 +/- 0.06% to 1.49 +/- 0.21% at 1 week. Hb concentrations increased from 103 +/- 5 g/l to 106 +/- 5 g/l at 2 weeks after the start of rhGH administration, and then increased gradually to reach the normal range. CONCLUSIONS: We conclude that EPO secretion was stimulated in the initial 2 weeks after the start of CSI of rhGH in anaemic patients with adult GH deficiency. Increased Hb concentrations after long-term administration of rhGH might be explained by direct stimulatory effects of rhGH and IGF-I on erythroid cells, which was accompanied by suppressed EPO secretion, in combination with a more generalized indirect impact of rhGH on physical activety. These findings suggest a beneficial effect of rhGH replacement in anaemic patients with adult GH deficiency.