Metabolic changes of cadmium and zinc in kidney and liver tissue
during foetal development in Romney and Merino sheep
J.R. Rounce, J. Lee, B.P. Treloar, N.D. Grace, B.R.Sinclair
AgResearch, Private Bag 11008, Palmerston North, New Zealand
Proceedings of the New Zealand Society of Animal Production. 1995,
55: 176-178
In adult sheep, cadmium (Cd) accumulates in both liver and kidney
tissue in an age dependent manner. To quantify the accumulation of Cd in
the developing foetus and investigate the relationship with the Cd status of
the maternal parent, liver and kidney samples were collected from both
Romney and Merino foetuses, approximately fortnightly, from 60 days after
conception up to parturition, and from the suckling lamb, weekly over three
weeks. Matching liver and kidney samples were also obtained from the dam.
Tissue sub-samples were analysed for metallothionein-mRNA by dot blot
hybridisation of total RNA extracts to assist in identifying regulatory aspects
of Cd accumulation in hepatic foetal tissue and any relationship with Zn.
Cadmium concentrations (means ± s.e.; ng Cd/g FW) in pre-parturition and
neonate Romney lamb liver (kidney) tissue compared with those in adult
were: 1.1±0.1 (2.5±0.25), 2.4±0.4 (2.8±0.4) and 139±8 (1208±99)
respectively. Merino tissue Cd concentrations were similar to those in the
Romney. Although Zn concentrations in liver tissue from the developing
foetus decreased with increasing gestation time, Cd concentrations remained
low and relatively constant over this period, but increased markedly after
parturition. There was no correlation between Cd in tissue from the dam and
that of the progeny and the data indicate that although placental transfer of
Cd is minor, a small influx of Cd from the dam into the foetal liver occurs
concomitantly with a much large flux of Zn into the developing liver
between 110-130 days after conception. Both Cd and Zn concentrations in
foetal and adult liver and kidney tissue were correlated with MT mRNA.
Keywords: NZSAPAB;
Cadmium; zinc; foetal development; placental transfer
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