COMPARATIVE STUDIES ON THE EFFECT OF DRUGS ON THE FIGURE OF CALCIFICATION OF INCISOR DENTIN OF THE RABBIT IN PREGNANCY AND OF THE NEONATE

The effects of 5, 000 u/kg of vitamin D2 and 800, 000 u/kg of vitamin D3 on calcification as well as on serum calcium, phosphate and alkaline phosphatase activity were investigated by using the striped calcification figure of rabbit's incisor dentin in the third trimester of pregnancy and of the neonate. The results were follows : 1) Hematoxylin-unstained layers in the dentin calcification figure, observed in the third trimester of pregnancy, turned blue or deep blue after the administration of 5, 000u/kg of vitamin D2 or 800, 000u/kg of vitamin D3, the effect of the former being stronger than that of the latter. In the dentin of the fetus, similar effects were observed, but they were weaker than in the mother rabbit. In the case of the fetus, the effects of vitamin D2 were also slightly stronger than those of vitamin D3. In comparison with the effects of calcium preparations (calcium lactate and calcium gluconate), the effects of vitamins D2 and D3 manifested dilatorily, but were nearly equal in the intensity.2) The tendency of decrease in serum calcium level in pregnancy was temporarily inhibited by the administration of vitamin D2 or D3, the effects of D2 being stronger than those of vitamin D3 as in the case of the striped figure of calcification. The tendency of decrease in inorganic phosphate in pregnancy was similarly inhibited in general by vitamin D2 or D3.The effect of vitamin D administration on serum alkaline phosphatase activity was not so clear.