Vitamin D-supplemented Group Research Articles

Immunocytochemical localization of rat intestinal vitamin D-dependent calcium-binding protein.

Vitamin D-dependent calcium-binding protein (CaBP) was localized in intestinal tissue sections obtained from rats raised under three different nutritional conditions: a normal vitamin D-replete diet, a vitamin D-free diet followed by supplementation with vitamin D3, or a vitamin D-free diet without additional supplementation. An indirect immunoperoxidase technique, with immunocontrols, was used to visualize the specific sites of CaBP. CaBP was visualized only in the cytoplasm of absorptive cells. In the duodenum of animals raised on a normal diet, CaBP was present in absorptive cells from the upper crypt region to the villus tips. In the jejunum, many fewer absorptive cells contained CaBP, while in the ileum only random absorptive cells near the villus tips contained CaBP. In rats raised on a vitamin D-deficient diet then supplemented with vitamin D3, CaBP was present in cells at the full depth of the crypts and in absorptive cells along the total villus length in the duodenum. Rats raised on the same deficient diet but without supplementation with additional vitamin D exhibited no CaBP in crypt cells nor in absorptive cells more than half way up the villi. Absorptive cells higher on the villi contained immunoreactive CaBP but the intensity of immunostaining and number of CaBP-containing cells was markedly reduced compared to the vitamin D-supplemented group.

Bone mineral content and serum 25-hydroxyvitamin D concentration in breast-fed infants with and without supplemental vitamin D

Eighteen term, healthy, appropriate for gestational age, breast-fed infants were studied in a double-blind prospective study to determine whether or not supplemental vitamin D affected bone mineralization. All patients were from a single, private pediatric practice. Nine infants were randomly assigned to a vitamin D supplement of 400 IU/day and nine infants to a placebo. By 12 weeks of age, infants receiving placebo had a significant decrease in bone mineralization and in serum 25-hydroxyvitamin D concentrations compared to the vitamin D-supplemented group. It is not known whether or not the increased BMC at 12 weeks of age in vitamin D-supplemented breast-fed infants is of ultimate value. Supplemental vitamin D may be necessary for optimal bone mineralization in term breast-fed infants. A longer follow-up study and additional analyses are required to make conclusive statements.

Lack of relation of pulp Ca 2+ -, Mg 2+ -ATPase to mineralization rate in rat incisor dentine in response to vitamin D and calcium intake

The role of pulp Ca 2+ -, Mg 2+-ATPase in the mineralization of dentine was examined by investigating the response of the enzyme to differing rates of mineralization. The rates were modified in weanling male rats by varying dietary calcium intake (0.02, 0.6 or 1.2 per cent Ca) and vitamin D intake (0 or 25 i.u./day). Mineralization of dentine was impaired in all vitamin D-deficient groups and in the low calcium, vitamin D-supplemented group. Pulp Ca 2+-, Mg 2+ -ATPase activity in the vitamin D-supplemented groups was not influenced by calcium intake, but was inversely related to calcium intake in the vitamin D-deficient groups. There was no correlation between mineralization rate and ATPase activity, and the enzyme activity was not clearly related to a deficiency of either calcium or vitamin D.