Brain regional thallium distribution in rats acutely intoxicated with Tl2SO4

The content of thallium in seven body organs and eight brain regions of rats acutely exposed to Tl2SO4 was compared. Rats received a single i.p. injection of Tl2SO4 at three doses: 16, 32 and 48 mg/kg. At 24 h after treatment, thallium content in kidney was higher than in all other organs studied and whole brain had the lowest thallium concentration. A thallium differential distribution was found among brain regions. The highest thallium concentration was found in the hypothalamus and the lowest in the cortex. This distribution pattern was similar with the three doses used. Time course of thallium accumulation in brain was found to be considerably more rapid in the hypothalamus than in other regions, particularly the cortex, suggesting differences in thallium entry into brain parenchyma. Thallium brain regional differential distribution might be related to some of the symptoms of thallium central neurotoxicity.