[Mineral and crystal formation "in vitro" by lipids extracted from bovine compact bone].

In order to study the role of lipids in the calcification process of the bone tissue, lipids have been extracted from undecalcified compact bone of calves less than 6 months old and from cows or oxen more than 2 years of age. Lipids from each group have been fractionned in "polar" and "non polar" types. Each type of lipid was shown to promote the formation of calcium phosphate precipitates in vitro. But only the polar lipids from calves bone promoted the formation of crystallised calcium phosphates, similar to hydroxyapatite. The identification of both crystallised and amorphous precipitates has been achieved by X-ray diffraction and chemical analysis.