Rat intestinal vitamin D-dependent calcium-binding protein: immunocytochemical localization in incisor ameloblasts.

Antiserum raised against the 10,000-Dalton vitamin D-dependent calcium-binding protein (CaBP10) from rat intestine was used to localize CaBP10 immunocytochemically in histological sections of rat mandible using an indirect immunoperoxidase method. Ameloblasts in the zone of maturation, along the continuously erupting incisor, contained CaBP10 throughout their cytoplasm. It was present in both smooth-ended ameloblasts and ruffle-ended ameloblasts. CaBP10 was not found in earlier developmental stages of ameloblasts or in other cells involved in tooth formation, i.e., odontoblasts, pulpal cells, cells of the stellate reticulum, papillary layer, and outer dental epithelium. The presence of CaBP10 in ameloblasts suggests that the vitamin D-endocrine system may have a direct effect on tooth formation in addition to the indirect effect of maintaining the required levels of serum calcium and phosphorus required for mineralization.