SELECTIVE EFFECT OF CHRONIC LEAD INGESTION ON TYROSINE HYDROXYLASE ACTIVITY IN BRAIN REGIONS OF RATS

概要

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Alterations of tyrosine hydroxylase activity in various regions of brain from rats postnatally exposed to lead were tested. Three groups of animals were prepared; (1) Rats exposed to lead at a low dose (0.05 % lead acetate, PbAc) ; (2) Rats exposed to lead at a high dose (0.2 % PbAc) ; (3) Age-matched normal control rats. At 2, 4, 6, and 8 weeks of age, weight of brain and body, and concentrations of lead in whole brain of animals in each group were measured. Activities of tyrosine hydlroxylase and Na^+-K^+ ATPase were also measured at the same ages in 4 brain regions of each animal. Body weight gain was decreased after 6 weeks of age in rats exposed to lead at a high dose. Concentrations of lead in whole brain were increased from 0.37 to 0.83 (ng/mg wet tissue) in these animals. Exposure of rats to lead generally increased tyrosine hydroxylase activity and decreased Na^+-K^+ ATPase activity. However, changes of tyrosine hydroxylase activity were detected without concomitant changes of Na^+-K^+ ATPase activity in pons-medulla at 2 weeks of age and telencephalon at 6 weeks of age in rats exposed to lead at a low dose, and in midbrain at 4 and 6 weeks of age in rats exposed to lead at a high dose. These data imply that catecholaminergic nervous system in the brain regions described above could be selectively affected by lead.
日本トキシコロジー学会の論文
1992-11-25