MARKERS OF BONE TURNOVER IN OSTEOPOROSIS

Osteoporosis is a slowly progressive bone disease, in which significan t bone loss occurs after a long period of time. Beside clinical invest igation, radiological assessment, osteodensitometry (DEXA, CT) and his tomorphometry, biochemical markers of bone turnover (enzymatic activit ies, circulating or excreted bone matrix components) were measured. Mo st of the conventional markers show normal values in osteoporosis, the refore it was necessary to develop more sensitive and specific markers of bone turnover, which allow to assess minimal changes of bone turno ver. Bone alkaline phosphatase (BAP), serum osteocalcin and the carbox y-terminal propeptide of type I collagen (PICP) reflect bone formation , urinary excretion of hydroxyproline and collagen pyridinium crosslin ks reflect bone resorption. Most of the other parameters of bone turno ver lack specificity or sensitivity, some of them have not yet been fu lly investigated. Regarding osteoporosis, one parameter of bone format ion and one parameter of bone resportion should be investigated.