Lipids in bone: optimal conditions for tissue storage prior to lipid analyses.

Optimal conditions for storage of calcified tissues prior to lipid analysis were determined by comparing the lipid composition (total lipid, total phospholipid, triglyceride, free fatty acid, cholesterol, and complexed acidic phospholipid) of mature rabbit diaphyseal bone stored 1, 2, and 5 months after animal sacrifice to that observed in the bones from which the lipids were immediately extracted at the time of sacrifice. Storage of lyophilized or nonlyophilized tissues at -70 degrees, or lyophilized tissues at -20 degrees, were the only methods that did not yield significant changes in bone lipid composition with time.