Objective   To study the change of parathyroid hormone(PTH)and calcitonin(CT)in serum at the early phase of skeletal fluorosis caused by fluoride in coal.

  Methods   SDrats were taken as the ex perimental objects, beingrandom assorted into 6 groups(the numbereither female or male was same in each group):control group, low dose fluoride group, middle dose fluoride and added nutrition group, middle dose fluoride group, high dose fluoride and added nutrition group, high-dose fluoride group.All rats were killed by means of arteria femoralis phlebotomy, then were examined dental fluorosis, fluo rine in urine, bone, kidney, bone mineral density(BMD), calcium in bone and urine, PTH and CT in serum.

  Results   (1) The estabolished animal model of fluorosis was successful.There were fluorosis in every test group and its all right for rats in the control group.The higher the fluoride dose, the more serious fluor osis syndrome of the rats.On the condition of same fluo ride dose, the fluorosis syndrome was mild if nutrition was good.(2)The effect of coal burning fluorosis on hormones correlated with skeletal metabolism a.PTH in serum PTH of the high dose group at the latter phase was higher than that at the earlier phase(P < 0.01);b.CT in serum At the earlier phase, CT had no manifest change; at the later phase, CT of the low dose and the middle dose and nutrition groups were higher than that of the control group(P < 0.05 or 0.01), CT of the low dose group was higher than that of the high dose group(P < 0.05).

  Conclusion   (1) The active of skeletal transduction probably is an important process in the genesis and development of fluorosis, at the earlier phase, skeletal formation active is more pan tent.(2)Neither PTH nor CT could be taken as the earlierindexes of skeletal fluorosis caused by fluoride in coal so far, (3) Reducing fluoride intake and improving nutrition can be used to release sydromes of fluorosis.