RESUMO
This study was performed in conscious male albino normal rats to determine the changes in Ca+2 excretion and its concentration in the serum following oral administration of prostaglandin synthesis inhibition by tiaprofenic acid [10 mg/kg] and piroxicam [1 mg/kg] for 21 days. It was found that tiaprofenic acid reduced the mean +/- SE 24-hour urinary Ca+2 excretion significantly after 10 and 21 days. This reduction did not reverse after one month from stoppage of its administration. Serum Ca+2 was lowered significantly after 21 days from its administration and persisted after one month from withdrawal of the drug. Piroxicam reduced significantly Ca+2 excretion and serum concentration of Ca+2 after 10 days and more reduction appeared after 21 days from administration. This reduction was not reversed after one month from stoppage of its administration. On the other hand, in arthritic rats, tiaprofenic acid reduced significantly urinary Ca+2 excretion and serum Ca+2 after 10 days from its administration and more reduction was observed after 21 days. As regads arthritic rats receiving piroxicam, it was found that 24-hour urine volume, urinary excretion of Ca+2 concentration were decreased significantly after 10 days from its administration. This reduction became more apparent after 21 days. One month after withdrawal of tiaprofenic acid and piroxicam, some improvement in these parameters was observed but still a significant reduction was noted compared with the control group [arthritic rats]