Use of perifusion to assess in vitro the functional integrity of interrenal tissue in teleost fish from polluted sites

A perifusion procedure adapted to field studies with fish was developed to assess in vitro the functional integrity of the cortisol-secreting interrenal tissue, which is distributed within the head kidney. The capacity of the interrenal tissue to respond to adrenocorticotropic hormone (ACTH) was assessed by stimulating isolated fish head kidney tissues with 10(-7) M of ACTH(1-39) during 10 min in perifusion, and monitoring the resulting increase in cortisol secretion. The interrenal tissue of yellow perch (Perca flavescens) from a site contaminated by a mixture of heavy metals and organic contaminants secreted significantly less cortisol in response to the standardized pulse of ACTH than did the interrenal tissue of fish from a reference site (54.7 +/- 8.9 vs 81.8 +/- 17.7 ng cortisol/g head kidney, respectively). These results indicate that the disruption of the cortisol stress response observed in fish from polluted sites is caused, at least in part, by a dysfunction of the interrenal tissue. The perifusion procedure can be used to examine the effects of chronic exposures to pollutants on the functional integrity of the cortisol-secreting interrenal tissue in teleost fish.