Effects of lead and/or zinc exposure during the second stage of rapid postnatal brain growth on delta-aminolevulinate dehydratase and negative geotaxis of suckling rats.

E. C. Goulart,C. Pereira,R. C. García,M. Giacomelli,A. L. S. Rodrigues

Published 2001 in Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas

ABSTRACT

Lead has been shown to produce cognitive and motor deficits in young rats that could be mediated, at least in part, by inhibition of the zinc-containing heme biosynthetic enzyme delta-aminolevulinate dehydratase (ALA-D). In the present study we investigated the effects of lead and/or zinc treatment during the second stage of rapid postnatal brain development on brain, kidney and blood ALA-D specific activity, as well as the negative geotaxis behavior of rats. Eight-day-old Wistar rats were injected intraperitoneally with saline, lead acetate (8 mg/kg) and/or zinc chloride (2 mg/kg) daily for five consecutive days. Twenty-four hours after treatment, ALA-D activity was determined in the absence and presence of DL-dithiothreitol (DTT). The negative geotaxis behavior was assessed in 9- to 13-day-old rats. Treatment with lead and/or zinc did not affect body, brain or kidney weights or brain- or kidney-to-body weight ratios of the animals. In spite of the absence of effect of any treatment on ALA-D specific activity in brain, kidney and blood, the reactivation index with DTT was higher in the groups treated with lead or lead + zinc than in the control group, in brain, kidney and blood (mean +/- SEM; brain: 33.33 +/- 4.34, 38.90 +/- 8.24, 13.67 +/- 3.41; kidney: 33.50 +/- 2.97, 37.60 +/- 2.67, 15.80 +/- 2.66; blood: 63.95 +/- 3.73, 56.43 +/- 5.93, 31.07 +/- 4.61, respectively, N = 9-11). The negative geotaxis response behavior was not affected by lead and/or zinc treatment. The results indicate that lead and/or zinc treatment during the second stage of rapid postnatal brain growth affected ALA-D, but zinc was not sufficient to protect the enzyme from the effects of lead in brain, kidney and blood.

PUBLICATION RECORD

  • Publication year

    2001

  • Venue

    Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas

  • Publication date

    2001-06-01

  • Fields of study

    Medicine, Chemistry, Environmental Science

  • Identifiers
  • External record

    Open on Semantic Scholar

  • Source metadata

    Semantic Scholar, PubMed

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