Catecholamine release and interrenal response of brown trout, Salmo trutta, exposed to aluminium in acidic water

Cannulated brown trout, Salmo trutta, were exposed for 36 h to synthetic water with a low calcium content of pH 5 and similar synthetic water dosed with aluminium to raise the filterable A1 from 5 to 290 μg 1−1 over the 36-h period. There were no significant disturbances of plasma concentrations of glucose, cortisol or catecholamine (adrenaline and noradrenaline) in fish held in water of pH 5. The addition of aluminium to this acidic synthetic water resulted in a generalized endocrine stress response with a four-fold increase in plasma glucose concentration after 18 h and a significant increase in plasma cortisol concentration from 24 h onwards when filterable A1 exceeded 200 μg 1−1. Plasma catecholamine concentration indicated an adrenergic stress response in aluminium-exposed brown trout. A transient doubling in noradrenaline after 6 h in A1 was followed by a larger increase in both plasma adrenaline and noradrenaline concentrations in fish surviving the 36-h exposure to A1.