The Effect of Recombinant Human Growthn Hormone on Prevention of Osteoporosis in Ovariectomized Rat

Lee, Young Goo; Choi, Jang Seok; Seo, Seung Seok; Kong, Kyu Min; Kim, Jin Wan

Abstract

GH concentration in plasma decline with age. GH and GH response to GHRH are influenced by sex hormones, thereby changing around the menopause. In several aspects, features of aging resemble those of a state of GH deficiency. It has been argued the declining GH function, along with other factors, might be a causal factor in osteoporosis. The purpose of this study was to investigate that postmenopausal osteoporosis in ovariectomized rat could be prevented by rhGH. Fifty-four Sprague-Dawley rats(weight 140-200g) were devided 3 groups. Group 1(n=18) was sham operation; Group 2(n=18) was ovariectomized and received subcutaneous injection with 0.05 cc normal saline; Group 3(n=18) was ovariectomized and received subcutaneous injection with 0.2 IU rhGH. Group 2 and 3 were injected daily, 6 day per week. Each group was devided three subgroups(n=6) and were sacrificed at 6 week, 10 week, 14 week, respectively. Group 2 showed a significant increase in body weight, femur length, serum IGF-1 level, serum PICP and ICTP level at 6 weeks, 10 weeks, 14 weeks and a significant decrease in ash weight of tibia, width of bony spicules, at 14 weeks than Group 1. Group 3 demonstrated a significant increase in body weight, femur length, serum IGF-1, serum PICP and ITCP levels and a insignificant decrease in ash weight of tibia and width of bony spicules, at 6 weeks, 10 weeks, 14 weeks than Group 1. At 14 weeks, Group 3 showed a significant increase in serum IGF-1, Serum PTH, Serum PICP. From these data, we conclude that although rhGH administration leads to an activation of bone turnover and more stimulation of bone formation, it does not prevent a bone loss in ovariectomized rat.