Managanese-induced biochemical changes in growing versus adult rats.

Manganese chloride was administered daily intraperitoneally to growing and adult rats for a period of 30 days to compare certain biochemical parameters in both groups of animals. Marked alterations in the levels of dopamine and norepinephrine in the brain was observed in manganese-treated growing rats. Furthermore, the contents of tyrosine, tryptophan in blood, liver, and brain have been significantly altered in these animals. Identical manganese administration to adult rats had no effect on the contents of tyrosine in liver and brain, nor tryptophan, and dopamine in the brain. Some of the parameters which were altered in the adult rats were less in magnitude compared to the growing animals. The experiments indicated higher susceptibility of the growing rats to the toxic effects of this metal.