THE SURFACE CHEMISTRY OF BONE

Abstract

Recent studies (l-3) have shown that powdered bone mineral, when suspended in a mineral buffer containing an isotope, can incorporate the labeled atoms by at least two processes.The first of these, adequately described as ionic ezchunge, is rapid, reversible, and surface-limited.The second, recrystallization, is relatively slow, temperature-sensitive, and involves the bulk of the crystal; i.e., it is not surface-limited.That ionic exchange occurs in vivo is generally agreed, although the terminology may vary somewhat (4-9).Recrystallization in vivo may be inferred from data in the literature (4-8), but no direct evidence has yet been presented.An experiment was performed with young adult rats.It was found that radiophosphate, given intraperitoneally, became fixed initially in the surfaces of the bone mineral, presumably by ionic exchange (5, 9).Gradually thereafter, the radiophosphate became incorporated in the interior of the mineral crystals.Thus, strong support was obtained for the hypothesis that the recrystallization of bone mineral occurs under normal physiological conditions.