In vitro and in vivo inhibition of Ca²⁺-Mg²⁺-ATPase activity by cadmium in post larvae of Penaeus monodon

Abstract

Ca²⁺-Mg²⁺-ATPase is a membrane-bound enzyme and is responsible for regulating cytosolic free calcium. In vitro and in vivo effects of cadmium were studied on Ca²⁺-Mg²⁺-ATPase activity in plasma membrane/mitochondrial fraction of Penaeus monodon post larvae. In vitro studies revealed a concentration-dependent decrease in enzyme activity with an IC₅₀ value of 11.02 µM. In vivo experiments were conducted by exposing the post larvae to 1/10th (0.12 ppm) and 1/5th (0.24 ppm) of LC₅₀ values of cadmium for 30 days. Both ATPase activity and metal accumulation were estimated in post larvae exposed to 0.12 and 0.24 ppm of cadmium at different intervals of 24 h, 48 h, 96 h, 10 days and 30 days. ATPase activity showed a gradual decrease in post larvae on exposure to both the sub-lethal concentrations with respect to their controls and the decrease was significant (p < .05) from 96 h onwards in post larvae exposed to 0.24 ppm and 10 days onwards on exposure to 0.12 ppm of cadmium. However, the effect of cadmium was higher in 1/5th than 1/10th sub-lethal concentration and also time-dependent. These enzyme studies were found to correlate with metal accumulation in post larvae at both the exposure concentrations. Disruption of calcium homeostasis might be one of the possible mechanisms of cadmium toxicity in these organisms.

Keywords:

• Cadmium
• Ca²⁺-Mg²⁺-ATPase
• Penaeus monodon
• post larvae
• tissue accumulation

Acknowledgements

The authors would like to thank the Head, Department of Zoology, Andhra University for providing the laboratory facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.