Circulating levels of 1,25 dihydroxyvitamin D, alkaline phosphatase, hydroxyproline, and osteocalcin associated with antler growth in white-tailed deer.

Alkaline phosphatase, hydroxyproline, osteocalcin, and 1,25(OH)2D were measured in biweekly serum samples obtained from 6 adult (greater than 4 years), 4 juvenile (1-4 years) and 4 fawn (less than 1 year) male white-tailed deer from Oct. 1983 to Oct. 1984. Antler length, from the pedicle to the tip, was measured at the time of serum sampling. Serum alkaline phosphatase activity and levels of hydroxyproline and osteocalcin were higher (P less than 0.05) in fawns compared with juveniles and adults reflecting increased bone metabolism in the younger deer. In adult deer serum alkaline phosphatase activity and hydroxyproline levels were elevated (P less than 0.05) during the period of antler growth, whereas serum osteocalcin and 1,25(OH)2D increased (P less than 0.05) during antler mineralization. Similar but less pronounced trends occurred in juvenile deer, possibly a reflection of skeletal growth in the younger animals. The data lend support for utilization of the deer antler cycle as a model for studies of bone disorders. Further work is needed to help clarify the role of hydroxyproline, osteocalcin, and 1,25(OH)2D in the antler cycle.