Suppression by organochlorines of the response to adrenocorticotrophin of the interrenal tissue in Sarotherodon aureus (Teleostei)

Superfused interrenal tissue of Sarotherodon aureus responded to ACTH with increased release of cortisol. The response to ACTH of interrenal tissue taken from fish treated with the organochlorine insecticide 1,1-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl) ethane (o,p-DDD; 50 mg/kg) in vivo was almost totally abolished. Lower doses were less effective. The response was also suppressed by exposure in vitro of the interrenal tissue to the organochlorine; there seemed to be a dose–response to o,p-DDD over the range of 0·023 to 1 mg/l. Also 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p′-DDE) was effective in suppressing the response to ACTH at concentrations of 50–150 mg/l; 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (p,p′-DDT) or the polychlorinated biphenyl, Aroclor 1254, were ineffective at 50 mg/l. No suppressive effect of o,p-DDD on output of cortisol could be detected in superfusion when N6,O2′-dibutyryl cyclic AMP (20 mmol/l) was substituted for ACTH. This may indicate that the interference of o,p-DDD with the interrenal response to ACTH results from an interruption in the generation of cyclic AMP.