Protein synthesis in rat brain following neonatal exposure to lead.
(1) Suckling rats were exposed to lead through the milk of their dams who received a diet of 4% lead carbonate and weanling rats were exposed to 2 injections of 5.0 mg Pb2+/100 g body weight. The brains were used to prepare the following homogenate fractions: postmitochondrial supernatant, postmicrosomal supernatant, ribosomes, initiation factors. (2) The postmitochondrial supernatant fractions were tested in vitro for protein synthesizing activity using the incorporation of labelled phenylalanine, and phenylalanyl-tRNA into peptide. The preparations from the lead-exposed rats had a significant reduction in activity. (3) Peptide formation with the brain ribosomes was not changed in the lead-exposed rats. (4) The aminoacyl-tRNA synthetase reaction was significantly reduced and accounted for most of the reduced peptide formation with brain homogenates from lead-exposed rats. (5) The binding of methionyl-tRNAfMet to ribosomes was increased using initiation factor preparations from the brain of lead-exposed rats.
D000828:Animal Population Groups / Q000502:physiology*; D000818:Animals; D000833:Animals, Suckling / Q000502:physiology*; D001921:Brain / Q000378:metabolism*; D015852:Eukaryotic Initiation Factor-2; D005260:Female; D007854:Lead / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D010448:Peptide Initiation Factors / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D015852:Eukaryotic Initiation Factor-2; D009419:Nerve Tissue Proteins; D010448:Peptide Initiation Factors; D011506:Proteins; D007854:Lead