Abstract: There is evidence that the biodistribution and the pharmacokinetics of 99mTc radiopharmaceuticals can be modified by some drugs, pathological stats, irradiation and surgical procedures. Tamoxifen have been widely used in various protocols of hormone therapy in the overall treatment of breast cancer. We have studied the effect of Tamoxifen on the biodistribution of technetium – 99m – methyl enediphosphonic acid (99m Tc-MDP), in female wistar rats (07 months old). We administered a single oral dose with 0.12 mg of Tamoxifen during 07 days. The animals (n=12) were divided in two groups: treated (n=6) and control (n=6) and they were sacrificed, respectively, in 2 periods (60 and 180 min), after administration of 99m Tc-MDP. The organs were isolated (lung, ovary, kidney, bladder, stomach, pancreas, spleen, heart, brain, bone, duodenum, thyroid, uterus, liver, muscle and blood) and the percentages of radioactivity (%ATI) in each organ were analyzed by the Wilcoxon test (P 0.05). The % ATI was significantly decreased in the uterus, ovaries, spleen, pancreas, heart, lungies, bone, muscle and brain of the animals, treated with tamoxifen (P 0.05) in both groups of 60 and 180 min. The treated group has show a significant increase of the ATI% in liver, kidney, bladder, stomach, thyroid and blood in 60 e 180 min.
L. M. Lopes De Britto , C. M. C. Xavier Holanda , R. L. Cavalcanti Jales , M. H. Marques Fonseca , L. H. Jales-Junior , K. C. Brand?o , L. F.Amorim and M. Bernardo-Filho , 2004. Effects of Tamoxifen on the Kinetic of Biodistribution of Radiopharmaceuticals in Wistar Rats . Journal of Animal and Veterinary Advances, 3: 208-212.