Cobalt induces alterations in serum parameters associated with bone metabolism in male adult rat

The intention of this study was to investigate the toxic effect of cobalt on the bone metabolism of rats, including calcium, inorganic phosphorus, and bone-specific alkaline phosphatase of serum during short-and long-term experiments. Rats were injected intraperitoneally (IP) with either 16 mg kg(-1) BW of cobalt for 5 and 10 days or 6 mg kg-1 BW for 20 and 40 days. It was found that IP administrations of cobalt could increase all serum parameters associated with bone metabolic processes. The observed effect was greatest for 16 mg kg-1 BW when used for 10 continuous days. By using gel filtration chromatography, we found that most of the activity of total serum alkaline phosphatase was related to low molecular weight isoenzymes, which can be used as a biomarker for bone metabolic disturbances. These results suggest that cobalt can induce bone resorption in adult rats and, therefore, behave as an osteoporotic agent.