Modificación del contenido de fósforo óseo en ratas tratadas con fluoruro de sodio (NaF). Factores intervinientes

ALFREDO RIGALLI

Rosario

Congreso; VI Congreso Sociedad Biología de Rosario; 2004

Sociedad de Biologia de Rosario

CHANGES IN BONE PHOSPHOROUS CONTENT (BPC) IN RATS TREATED WITH SODIUM FLUORIDE (NaF). Di Loreto V, Moreno H,  Rigalli A, Puche RC. Lab Biol Ósea. Facultad de Ciencias Médicas. UN Rosario   Administration of NaF increases bone mass in rats. Nevertheless, the composition and quality of bone formed under fluoride (F) stimulus is still matter of study. The aim of this work was to investigate the effect of treatment with NaF on BPC in rats and the factors which modify it. Experiments were carried out in 50-day old female rats IIM/FcM. Exp.1: 4 groups of 4 rats each were given the following  doses (mmol/day.100g bw ) of NaF: Group A: 0, B: 20, C: 40 y D: 60. After 30 days rats were killed and femurs were excised. BPC (mg/g dry bone) decreased as a function of F dose. A: 93±14: B: 79±16; C: 61±15a; D: 60±9a , p<0,01 a states differences with regards to group A. In the following experiments, the F dose was 40 mmol/day.100g bw, by gastric tube. Exp 2: 4 rats received one dose of F. Phosphatemia (mg/dl) increased significantly (basal: 8.7±0.6, 60 min: 13.0±0.3 p<0.001) and phosphaturia (mg) decreased during the 1st hour. Exp 3: Renal and plasmatic flow, and glomerular filtration were not affected after F administration (n=4). Exp 4: 4 thyroparathyroidectomized (TX) rats received one dose of F. Phosphatemia increased in both groups but F did not modify renal handling of phosphate in TX. Exp 5: Phosphate concentrations in erythrocyte of rats after one dose of F did not change, although phosphatemia increased steadily. Conclusions: The treatment with F decreased BPC. One cause of this change would be the effect of F in renal phosphate handling. Neither renal hemodynamia nor the inhibitory effect on PTH actions would be the causes of disruption in phosphate renal handling. Efflux of phosphate from cells might not be the cause of the increase in phosphatemia.