ABSTRACT
The effect of dipyrone (N-2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl)-methyllamino methanesulfonate sodium monohydrate) on the placenta of 2 BAW albino rats was studied through Karyometry of trophoblastic giant cells and DNA, RNA and total protein determinations. The animals received a single daily dose of 50 mg/Kg body weight during different periods of pregnancy: from the 9th to the 12th, 11th to the 14th, 13th to the 16th, 15th to the 18th and 17th to the 20 thday. Control animals received a single daily dose of 0.5ml distilled water at the same time. Karyometric results showed a statistically significant increase in nuclear volumes of placental cells of rats receiving dipyrone during the first three periods, when compared to control groups. In the two groups that received the drug nearer to term there was no significant difference. Regarding DNA, RNA and total protein determinations, there was a statistically significant difference, for all of them, in the rats that received the drug from the 9th to the 12 th day of pregnancy when compared to the control group. There was no significant difference in the groups that received the drug after that period. The results show that dipyrone had a blocking effect on cell division and that this effect happens mainly in the initial period of placental development