Effects of growth hormone and insulin-like growth factor-1 on protein metabolism, gut morphology, and cell-mediated immunity in burned rats

The effects of recombinant human growth hormone (GH) and insulin-like growth factor-1 (IGF-1) were investigated in burned rats. Sprague-Dawley rats were fed exclusively by total parenteral nutrition and were subjected to 20% third-degree scald burns. The rats were then divided into the following three groups: (1) the GH group received GH at a dose of 1 IU·kg−1·d−1 for 2d (n = 10); (2) the IGF group received IGF-1 at a dose of 4 mg·kg−1·d−1 for 2d (n = 19); and (3) the control group received saline (n = 17). Cumulative nitrogen balance increased significantly in the GH (P < 0.01) and IGF (P < 0.01) groups as compared with the control group. There were no differences in nitrogen balance between the GH and IGF groups. Blood glucose was decreased in the IGF group (P < 0.01) and increased in the GH group (P < 0.05) as compared with the control group. The intestinal villus height and wall thickness of the GH and IGF groups were significantly greater than those of the control group. Delayed-type hypersensitivity was enhanced in both the GH and the IGF groups as compared with the control group (both P < 0.01). Furthermore, the increase in the IGF group was significantly greater than that in the GH group (P < 0.05). It was concluded that both GH and IGF-1 improve protein metabolism and immune responsiveness, as well as promote proliferation of the intestinal mucosa.