Effect of cadmium on lung lysosomal enzymes in vitro.

Labilization of lysosomal enzymes is often associated with the general process of inflammation. The present study investigated the effect of the pneumotoxin cadmium on the release and activity of two lung lysosomal enzymes. Incubation of rat lung lysosomes with cadmium resulted in the release of beta-glucuronidase but not acid phosphatase. The failure to "release" acid phosphatase appears to be the result of a direct inhibitory effect of cadmium on this enzyme. The K1 for cadmium was determined to be 26.3 microM. The differential effect of cadmium on these two lysosomal enzymes suggests that caution should be exercised in selecting the appropriate enzyme marker for assessing lysosomal fragility in the presence of this toxicant. Furthermore, the differential basal release rate of the two enzymes from lung lysosomes may reflect the cellular heterogeneity of the lung.