Changes in tissue glutathione levels in the cichlid oreochromis aureus (steindachner) following long term exposure to mercury, cadmium and lead

Abstract

Oreochromis aureus was exposed to the metals cadmium, mercury and lead individually, or as mixtures of two metals, for 140 days. At least 2 different concentrations of each metal were used. Seven or eight different fish tissues were analysed for reduced glutathione (GSH) content at the end of the exposure period with the objective of identifying tissues which would give a characteristic change in GSH concentration in response to heavy metal pollution. Significant changes observed in tissue GSH concentrations were all increases, with few exceptions. The most commonly occurring response was an increase in kidney GSH content. This always occurred following exposure to cadmium, at all concentrations and in the persence of other metals. Therefore elevated renal GSH levels might serve as indicatiors of cadmium exposure.

Key words:

• Glutathione status
• heavy metals
• mercury
• cadmium
• lead