Figure 1514

The importance of cellular transport in mediating toxicity. Proximal tubular uptake of inorganic mercury is thought to be the result of the transport of mercuric conjugates (eg, diglutathione mercury conjugate [GSH-Hg-GSH], dicysteine mercuric conjugate [CYS-Hg-CYS]). At the luminal membrane, GSH-Hg-GSH appears to be metabolized by (-glutamyl transferase ((-GT) and a dipepti-dase to form CYS-Hg-CYS. The CYS-Hg-CYS may be taken up by an amino acid transporter. At the basolateral membrane, mercuric conjugates appear to be transported by the organic anion transporter. (-Ketoglutarate and the dicarboxylate transporter seem to play important roles in basolateral membrane uptake of mercuric conjugates. Uptake of mercuric-protein conjugates by endocytosis may play a minor role in the uptake of inorganic mercury transport. PAH—para-aminohippurate. (Courtesy of Dr. R. K. Zalups.)

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