PATHWAYS OF CR-(III) AND CR-(VI) IN THE RAT AFTER INTRATRACHEAL ADMINISTRATION
51-Cr labelled Cr**3+ and CrO-4**2- solutions were administered intratracheally to male rats in doses of 0.1 and 10 mug of Cr per rat to evidentiate metabolic differences especially in the lung and in the mechanisms of excretion. Twenty four hours after administration the highest 51-Cr amount was present in the lungs for both valency states, being in the Cr (III)-treated group, however, about two times higher. In all other tissues tested the values in the Cr (VI)-treated animals were much higher. Intracellularly, in the Cr(III)-treated group more than 40% of the total lung homogenate was found in the nuclear fraction and only 10% in the cytosol. In the Cr(VI)- treated group 25% was present in the nuclei and more than 50% in the cytosol. Gel filtration 24 h after intratracheal injection showed that in both cytosols chromium was eluted in three peaks including a low molecular weight component. Quantitatively, however, the ratios between the 51-Cr associated with the three peaks were significantly different between the Cr (III)- and the Cr (VI)-treated animals. This suggests that binding of chromium to low molecular-weight components should be involved in the passage of this element from the lung to the other tissues. Excretion studies for 7 days showed that after this time the Cr (III)-treated animals excreted about 4% of the dose via urine and more than 36% via faeces, whereas in the Cr (VI)-treated rats the 51-Cr was eliminated nearly equally between urine and faeces.
Bibliographic Reference: HUMAN TOXICOLOGY, VOL. 4 (1985), PP. 409-416.
Record Number: 1989124019900 / Last updated on: 1987-01-01
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