ABSTRACT
The aim of the current study was to evaluate the therapeutic role of some amino acids in the management of osteoporosis in ovariectomized [OVX] rats. This study was conducted on 56 adult female rats which were divided into 7 groups as follows: Gp.[1] OVX rats orally administered with [1 ml/rat/day] saline as vehicle; Gp.[2] OVX rats orally administered with L-lysine [1.26g/kg/b.wt.]; Gp.[3] OVX rats orally administered with L-arginine [500mg/kglb.wt.]; Gp.[4] OVX rats orally administered with L-glutamine [3.2g/kg/b.wt.]; Gp.[5] OVX rats orally administered with taurine [50mg/kglb.wt.] and Gp.[6] OVX rats orally administered with a combination of the four amino acids dissolved in saline. In addition, gonad-intact [control group] orally administered with 1 ml saline/rat/day was involved in the present study. The treatment was started after 3 months of ovariectomy and continued for other 3 months. Serum calcium [Ca], phosphours [P], parathyroid hormone [PTH], osteocalcin [OC], insuline like growth factor-1 [IGF-1], transforming growth factor-beta [TGF-beta] levels and bone alkaline phosphatase [BAP] activity were determined. Significant decrease in serum Ca, P levels and bone ALP activity as well as in serum OC, IGF-1 and TGF-beta levels were ovariectomy-induced, while it caused significant increase in serum PTH level when compared to their corresponding values in gonad-intact control rats. Treatment of OVX rats with L-lysine or L-arginine produced non-significant increase in serum Ca and P levels and the treatment with L-glutamine or taurine induced significant increase in serum Ca and P levels. Treatment with either one of the selected amino acids resulted in significant decrease in serum PTH level while these amino acids produced significant increase in serum osteocalcin level and BAP activity. Treatment of OVX rats with L-lysine induced non-significant increase in serum IGF-1 and TGF-beta, while the combination of L-arginine with either L-glutamine or taurine produced significant increase in serum IGF-1 and TGF-beta. Treatment of OVX rats with a combination of the selected amino acids resulted in significant increase in the all studied biochemical parameters except serum PTH level which showed significant decrease as compared to their corresponding values in OVX rats. Each of the selected amino acids or their combination significantly modulates markers of bone turnover in OVX rats. These results indicated the usefulness of these amino acids in the treatment of primary osteoporosis