Abstract-The effects of DDT compounds on the function and viability of interrenal corticosteroidogenic tissue were investigated in vitro in rainbow trout (Oncorhynchus mykiss) in a dose-response study. The o,pЈ-dichlorodiphenyldichloroethane (DDD) was the most potent of the tested chemicals in decreasing adrenocorticotropic hormone (ACTH)-stimulated cortisol secretion by head kidney fragments compared with controls. The dbcAMP-stimulated cortisol secretion was also impaired with doses of 50 and 100 mg/L o,pЈ-DDD but not 25 mg/L. Tissue viability, estimated by the release of lactate dehydrogenase (LDH), was similar to controls at 25 mg/L and was decreased significantly at 50 and 100 mg/L o,pЈ-DDD. These results suggest that o,pЈ-DDD is an adrenotoxic compound that may disrupt the 3Ј,5Ј-monophosphate (cAMP) generation step and, at higher doses, induce irreversible cytotoxic effects. The p,pЈ-DDT induced a significant inhibition in the secretory response to ACTH and dbcAMP only at 100 mg/L, while p,pЈ-DDD had no effect on the cortisol secretion. A significantly decreased viability was detected at the higher doses of p,pЈ-DDT and p,pЈ-DDD without a detectable disruption of cortisol synthesis. The steroidogenic interrenal cells may be less sensitive to the DDT compounds tested than other cell populations within the teleost head kidney.

The organochlorine o,p'- dichlorodiphenyldichloroethane (o,p'-DDD) is a metabolite of dichlorodiphenyltrichloroethane (DDT), known for its adrenolytic actions in birds and mammals. The effects of o,p'-DDD on the cortisol stress response were investigated in rainbow trout, Oncorhynchus mykiss, in a dose-response study in vivo. A dose-dependent decrease in plasma cortisol levels was observed on days 7 and 14 after a single i.p. injection of o,p'-DDD. Treatment with o,p'-DDD had no effect on weight gain, hematocrit, and gonado- or hepatosomatic index but decreased liver glycogen reserves. The results indicate that o,p'-DDD is an adrenotoxic compound in rainbow trout and that its effects can be detected even 14 d postinjection.

The effects of DDT compounds on the function and viability of interrenal corticosteroidogenic tissue were investigated in vitro in rainbow trout (Oncorhynchus mykiss) in a dose-response study. The o,pЈ-dichlorodiphenyldichloroethane (DDD) was the most potent of the tested chemicals in decreasing adrenocorticotropic hormone (ACTH)-stimulated cortisol secretion by head kidney fragments compared with controls. The dbcAMP-stimulated cortisol secretion was also impaired with doses of 50 and 100 mg/L o,pЈ-DDD but not 25 mg/L. Tissue viability, estimated by the release of lactate dehydrogenase (LDH), was similar to controls at 25 mg/L and was decreased significantly at 50 and 100 mg/L o,pЈ-DDD. These results suggest that o,pЈ-DDD is an adrenotoxic compound that may disrupt the 3Ј,5Ј-monophosphate (cAMP) generation step and, at higher doses, induce irreversible cytotoxic effects. The p,pЈ-DDT induced a significant inhibition in the secretory response to ACTH and dbcAMP only at 100 mg/L, while p,pЈ-DDD had no effect on the cortisol secretion. A significantly decreased viability was detected at the higher doses of p,pЈ-DDT and p,pЈ-DDD without a detectable disruption of cortisol synthesis. The steroidogenic interrenal cells may be less sensitive to the DDT compounds tested than other cell populations within the teleost head kidney.

The organochlorine o,p'- dichlorodiphenyldichloroethane (o,p'-DDD) is a metabolite of dichlorodiphenyltrichloroethane (DDT), known for its adrenolytic actions in birds and mammals. The effects of o,p'-DDD on the cortisol stress response were investigated in rainbow trout, Oncorhynchus mykiss, in a dose-response study in vivo. A dose-dependent decrease in plasma cortisol levels was observed on days 7 and 14 after a single i.p. injection of o,p'-DDD. Treatment with o,p'-DDD had no effect on weight gain, hematocrit, and gonado- or hepatosomatic index but decreased liver glycogen reserves. The results indicate that o,p'-DDD is an adrenotoxic compound in rainbow trout and that its effects can be detected even 14 d postinjection.