In vivo absorption of l-leucine by the intestine of the toadfish Opsanus tau - the effect of several heavy metal compounds

Increasing fluxes of heavy metals into coastal waterways and the accumulation of these toxicants in marine organisms cause a variety of biochemical and physiological dysfunctions. We have studied the effect of several heavy metal compounds on the membrane transport of essential nutrients in the intestine of fish. Using an in vivo technique, the effects of HgCl 2, CH 3HgCl and CdCl 2 on the absorption of the essential amino acid, l-leucine, by the intestine of the toadfish, Opsanus tau, were examined. HgCl 2 is the most potent inhibitor of intestinal l-leucine absorption among the heavy metal compounds tested. HgCl 2 appears to act on the active transport and facilitated diffusion components of uptake. CH 3HgCl possibly acts on the active transport component. |CdCl 2 appears to affect only a low affinity facilitated diffusion component. Several mechanisms of action for the heavy metals are proposed.