Increased growth hormone response to growth hormone releasing hormone induced by erythropoietin in uraemic patients

This study was designed to assess the response of growth hormone (GH) to growth hormone releasing hormone (GHRH) and the possible interaction of acutely administered recombinant human erythropoietin (rhEPO) on GH response to GHRH in a group of uraemic patients. Eight patients on maintenance haemodialysis, not previously treated with rhEPO, and six healthy controls were tested with GHRH (100 micrograms i.v. in bolus), and with GHRH (100 micrograms i.v. in bolus) plus rhEPO (40 U/kg in constant infusion for 30 min) on different days. GHRH injection provoked a GH release in five out of eight uraemic patients; the overall mean response did not differ significantly from the GH response obtained in controls (P = 0.30). Erythropoietin infusion significantly increased GH release after GHRH (P less than 0.01 at 15, 30, 45, 60 min after GHRH injection) in uraemic patients; in controls, on the contrary, stimulation with GHRH plus rhEPO did not induce a greater increase of GH release compared with that observed after GHRH alone (mean GH peak 37.66 +/- 7.68 mU/l after GHRH; and 38.0 +/- 9.18 mU/l after GHRH plus rhEPO; P greater than 0.5). In this study acutely administered rhEPO significantly potentiated the GH response to GHRH in uraemic patients whereas the same effect was not demonstrable in subjects with normal renal function.