The effect of hypermagnesemia on serum levels of osteocalcin in an animal model

Using a pregnant goat (Capra hircus) model to study the in vivo effects of hypermagnesemia on serum osteocalcin concentration, magnesium sulfate infusion has been shown to increase circulating levels of osteocalcin. At 2 h after the administration of magnesium sulfate, a 98% increase in Mg²⁺ concentration over the basal level resulted in: a 38% increase in serum osteocalcin concentration over baseline; a 22% decrease in PTH concentration, and no change in total and ionized calcium concentrations. These in vivo data support previous in vitro results demonstrating that Mg²⁺ is a potent inhibitor of osteocalcin binding to hydroxyapatite.