Impact of lead toxicity on brain metabolisms of nucleic acid and catecholamine in protein malnourished rats.
The brain biochemistry in terms of certain key substances of brain were studied in 18% protein and 6% protein-fed rats following lead ingestion at a level of 1% in the diet. Lead ingestion diminished the protein and increased the RNA content of brain, and, consequently reduced the protein/RNA ratio. The RNA/DNA ratio in brain was elevated in lead toxicity, while the protein/DNA ratio remained unaltered. The RNase and DNase activities of brain were decreased. Lead treatment diminished the glutathione (GSH) level of blood but the GSH level of brain was not altered significantly by the lead treatment. The plasma protein level was also diminished after lead treatment. The effects of lead on some of these parameters were found to be more pronounced in rats receiving the 6% protein diet. The serotonin (5-HT) level of brain was reduced, while the norepinephrine (NE) and dopamine (DA) levels of brain were elevated following lead treatment. The monoamine oxidase (MAO) and tryptophan hydroxylase (TPH) activities and 5-hydroxy-indole acetic acid (5-HIAA) content of brain were elevated in lead-ingested rats. The effects of lead on these parameters were found to be potentiated when the rats were fed on a 6% protein diet. These studies suggest that lead at the present dose affects brain biochemistry in terms of both nucleic acids and amine metabolism, and protein deficiency potentiates some of these lead-induced changes.
Ghosh
S
S
Department of Physiology, Calcutta University College of Science, India.
Chatterjee
A K
AK
Gupta
M
M
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism*; D007854:Lead / Q000633:toxicity*; D008297:Male; D009696:Nucleic Acids / Q000378:metabolism*; D011488:Protein Deficiency / Q000378:metabolism* / Q000503:physiopathology; D011502:Protein-Energy Malnutrition / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D002395:Catecholamines; D009696:Nucleic Acids; D007854:Lead