Abstract
The effects of fluoride (F) on the growth, protein synthesis, alkaline phosphatase (ALP) activity, cyclic adenosine 3', 5'-monophosphate (cAMP) levels and ultrastructure were examined in normal human diploid cells (NDU-1 cells, fibroblasts) derived from fetal lung tissue.
Concentrations of F between 0.026mM-0.53mM had no effect on the growth of NDU-1 cells. However, 0.79mM F depressed the growth of the cells and 1.05mM F led to complete inhibition of growth. Reduced protein synthesis (incorporation of 14C-leucine) was observed with 0.79mM F, but, 0.026mM F and 0.53mM F slightly enhanced protein synthesis to 109% and 108% of the control, respectively.
After 24 hours of exposure to concentrations of 0.026mM-1.05mM F, ALP activity in the cells was increased in a manner similar to that of control cells. However, ALP activity in cells treated with 2.63mM F seemed to be strongly depressed.
The cAMP values increased rapidly after the addition of 2.63mM F.
Cells cultured for 24 hours with 0.026mM F or 0.53mM F contained a well-developed, roughsurfaced endoplasmic reticulum (rER) when compared with control cultures. In cells treated with 0.79mM F or 1.05mM F, numerous lysosomes and a less-developed rER were observed. Many vacuoles were also observed in the 2.63mM F treated cells.
In conclusion, the higher concentrations of F tested inhibited cell growth and protein synthesis, but the lower concentrations of F accelerated protein synthesis. These findings are supported by morphological investigation. Finally, F had a stimulatory effect on cAMP, but a depressant effect on ALP activity.
