Alterations in human serum alkaline phosphatase and its bone isoenzyme by chronic administration of lithium.

There are conflicting data on the effects of lithium on bone metabolism. Bone formation is known to be reflected by the activity of alkaline phosphatase of the bone tissue. We have found significant differences in mean serum alkaline phosphatase and its bone isoenzyme levels between a group receiving lithium and a control group. In this study increased bone isoenzyme of alkaline phosphatase activity above the normal range was found in 27 of 41 patients treated with lithium carbonate. In 19 of 41 patients treated with lithium the activity of bone isoenzyme was increased above the normal range even in the absence of increased activity of serum total alkaline phosphatase.