Potential Effects of Recombinant Human Growth Hormone (r-hGH) on Somatic Growth in Uremic Rats

Abstract

In this study, we investigated both the efficacy of growth hormone (GH) in the improvement of growth disturbances in uremia and the effects on the remaining kidney, using uremic rats. Twenty 5/6 nephrectomized uremic rats were divided into two groups. One half of them were injected intraperitoneally with 2IU of human recombinant growth hormone (r-hGH) twice daily. The others were injected only with the vehicle. Sham operated control rats were also injected with the vehicle. These rats were pairfed and observed for as long as 4 weeks, during which, the growth in stature in uremic rats without r-hGH was markedly retarded, with a gain of only 15.8 +/- 3.7 mm of body length. It was significantly less than the 48.0 +/- 5.1 mm (p less than 0.01) gained by control sham-operated rats. By contrast uremic rats treated with r-hGH gained 37.8 +/- 2.9 mm, which was significantly greater than uremic rats without r-hGH (p less than 0.01) but less than controls (p less than 0.01). Increments of body stature paralleled those of skeletal bones. The food utilization rate was significantly improved in uremic rats treated by r-hGH. Throughout the experiment, serum creatinine and urea nitrogen levels remained constant and there were no intergroup differences in the uremic rats including insulin like growth factor I (IGF-1) and other chemical parameters except for plasma GH levels. These results suggest that r-hGH stimulates somatic growth in rats with chronic renal failure through improving food utilization and a probable direct effect on growing cartilage.