Inhibition of Ca²⁺ uptake in freshwater carp, Cyprinus carpio, during short‐term exposure to aluminum

In carp exposed to pH 5.2 in fresh water, the Ca²⁺ influx from the water is reduced by 31% when compared to fish in water of neutral pH. At pH 5.2, the Ca²⁺ influx but not Na⁺ uptake is decreased by aluminum (Al). Al reduces Ca²⁺ influx dose‐dependently: a maximum 55% reduction was observed after 1–2 h exposure to 200 μg·1⁻¹ (7.4 μM) Al. Branchial Ca²⁺ efflux is less sensitive to Al and affected only by exposure for more than 1 h to high Al concentrations. Na⁺ influx is not affected by concentrations Al up to 400 μg·1⁻¹. Na⁺ efflux, similarly to Ca²⁺ efflux, increased when fish were exposed for more than 1 h to 400 μg·l⁻¹ Al. © 1992 Wiley‐Liss, Inc.