Bone isoenzyme of serum alkaline phosphatase in diabetes mellitus.

Increased activity of bone isoenzyme of serum alkaline phosphatase was found in 52, 82 and 72% of the patients on dietary, oral agents, and insulin regimens, respectively. Significant positive correlations between the activity of bone isoenzyme and urinary hydroxyproline excretion in diabetes are similar to those found in osteoporosis. In stepwise regression analysis, negative correlations were found between the parameters of turnover of bone organic matrix and serum calcium levels; the influence of blood glucose levels in the expression of the biochemical parameters of bone metabolism was most pronounced in patients on oral agents. The results explain moderate hyperphosphatasia, known in diabetes, and support a metabolic etiology for the bone disease in diabetes mellitus.