Effect of trimethyltin on ornithine decarboxylase in various regions of the mouse brain.

Male C57B1/6N mice, 8-10 weeks old were given a single oral dose of 0, 1.0 or 3.0 mg/kg body weight of trimethyltin hydroxide (TMT). Levels of ornithine decarboxylase (ODC) activity were measured in several brain areas, 1, 2 and 7 days later. The lower dose of TMT produced a decrease of ODC in the caudate nucleus and hippocampus at all time points studied. Hypothalamus, cerebellum and brain stem levels of this enzyme were unaltered. At the higher dose of TMT, ODC activity in hippocampus, cerebellum and brain stem were increased relative to controls at 1 and 2 days after treatment, while other regions were not significantly affected. These elevated ODC levels returned to control values within 7 days. Thus, trimethyltin treatment causes changes in ODC activity in a region and dose-specific manner.