Effect of calcitonin or the anabolic steroid Decadurabolin on serum beta 2 microglobulin in osteoporotic postmenopausal women.

beta 2-Microglobulin (beta 2m) is a small polypeptide of 99 amino acids with a molecular weight of 11.800. It is found in serum, on the surface of almost all mammalian cells and is part of the surface antigen of the cell membrane of human lymphocytes. Moreover, the heavy chain of major histocompatibility complex class I molecules normally associates in the membrane with beta 2m. According to Canalis, et al this polypeptide is a bone derived growth factor. In our study, serum beta 2m, osteocalcin bone Gla-protein (BGP) and calcium phosphorous metabolism were evaluated in a group of 18 osteoporotic women. Nine were treated with an anabolic steroid, DecaDurabolin and 9 with salmon calcitonin (sCT) for 3 months. The same variables were evaluated in a control group (6 osteoporotic women) treated with oral Ca (1,500 mg/day for 3 months). A significant increase in serum beta 2m and BGP (p < 0.001) was observed after anabolic steroid while a significant decrease in serum beta 2m and BGP (p < 0.01) was observed after sCT. No significant variation for serum beta 2m and BGP was observed in the control group. No significant variation of calcium-phosphorous metabolism was observed in either the control group or the treated group. BGP variations suggest that anabolic steroid stimulates bone formation while a decrease in BGP observed after sCT suggests that this hormone depresses bone turnover via a block in osteoclast activity. Moreover it could be suggested that anabolic steroid and sCT affect beta 2m producing cells.