Effects of vitamin D3 injection on activity of thyroid parafollicular cells in pregnant rats.

ABSTRACT

Effects of vitamin D3 (VD3) injection on the activity of thyroid parafollicular cells (C cells) and calcium (Ca) metabolism were examined in rats of non-(NP), middle (MP) and late pregnancy (LP). At 3 days after injection, the average area of a C cell was significantly wider (P<0.01) in the VD3 groups than that in their control groups in NP, MP, and LP. On the otherhand, the plasma ca concentration in the VD3 groups decreased significantly (P<0.05) in comparison with that in their control 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 non-pregnant and pregnant rats.