| Abstract: | The heavy metals iron and lead are taken up and metabolized in a similar manner by the crayfish hepatopancreas, but only lead appears to enter cells of the antennal gland (green gland). Iron, on the other hand, which apparently is not taken up by the antennal gland cells following systemic injections of low doses (0.05 mg), exerts striking alterations in cell ultrastructure after pericardial injections of massive doses (0.5 mg). Electron microscopic examination and atomic absorption spectrophotometric analyses of the hepatopancreas and antennal glands of iron-injected crayfish revealed that iron was selectively stored in metal-containing vacuoles of R- and F-cells in the hepatopancreatic cells, where it accumulated in concentrations that were toxic to these cells. High doses of iron caused alterations in the ultrastructural morphology of the cells of the antennal glands, although no accumulation of iron was apparent. Lead was similarly stored in metal-containing vacuoles of the cells of the hepatopancreas of lead-injected crayfish, but also accumulated in high concentrations (prior to being excreted) in vacuoles, cytoplasmic bodies and vesicles in the cells of the antennal gland. In contrast, lead in high concentrations was relatively non-toxic to any of these cells, suggesting that crayfish were more efficient in detoxifying and eliminating lead than iron. |
