EFFECTS OF VITAMIN-D-3 INJECTION ON ACTIVITY OF THYROID PARAFOLLICULAR CELLS IN PREGNANT RATS

Effects of vitamin D-3 (VD3) injection on the activity of thyroid para follicular cells (C cells) and calcium (Ca) metabolism were examined i n rats of non-(NP), middle (MP) and late pregnancy (LP). At 3 days aft er injection, the average area of a C cell was significantly wider (P< 0.001) in the VD3 groups than that in their control groups in NP, MP a nd LP. On the other hand, the plasma Ca concentration in the VD, group s decreased significantly (P<0.05) in comparison with that in their co ntrol groups in NP and LP, and tended to decrease in MP. These results suggest that injection of VD3 may accelerate the activity of C cells, which may result in the decrease of plasma Ca concentration in both n on-pregnant and pregnant rats.