Increase in haemoglobin concentrations in growth hormone deficient adults during human recombinant growth hormone replacement therapy.

OBJECTIVE

Recombinant human growth hormone is being used increasingly in the treatment of GH deficiency in adults. In addition to erythropoietin, insulin-like growth factor-I (IGF-I) has been demonstrated to stimulate hematopoiesis in animals, especially rodents. We have determined the effect of growth hormone (GH) administration on haematopoiesis.

PATIENTS AND DESIGN

Seventeen patients (10 males and 7 females; mean age 47 +/- 2 years; range 30-59) with biochemically proven adult-onset GH deficiency (GHD) were treated with human recombinant growth hormone (rhGH) as replacement therapy for more than 96 weeks in a dosage of 12.5 micrograms/kg/day (initial dosage during the first 4 weeks 6.25 micrograms/kg/day). The diagnosis of GHD had been confirmed using a standard arginine-infusion test (0.5 g/kg body weight). Blood samples were collected for safety and efficacy parameters before and during the GH treatment period.

MEASUREMENTS

Routine methods were used for the haematological and biochemical measurements. IGF-I concentrations were measured, using a commercial RIA kit.

RESULTS

From week 36 and onwards, we observed a significant increase in individual haemoglobin (Hb) concentrations, especially in the male patients. Mean Hb in the male patients before treatment amounted to 9.1 +/- 0.2 mmol/l (range 8.1-10.5) and increased by 0.93 +/- 0.2 mmol/l (P < 0.05) after 120 weeks of rhGH replacement therapy. The mean Hb concentration in female patients before treatment was 8.1 +/- 0.1 mmol/l and an increase of 0.32 +/- 0.1 mmol/l (P < 0.05) was observed after 120 weeks. For all 17 patients the mean increase in Hb after 120 weeks was 0.73 +/- 0.2 mmol/l (P < 0.05). IGF-I concentrations also increased during therapy from 86 +/- 9 pg/l to 253 +/- 26 pg/l within 24 weeks (P < 0.05). No significant changes in leucocyte or platelet counts were found.

CONCLUSIONS

Long-term replacement therapy with rhGH in patients with adult-onset GHD induces a significant increase in Hb concentrations, while serum leucocyte and platelet counts do not change.