Techniques to determine interaction of 

 chlorinated hydrocarbons with a specific enzyme 

 or metabolic pathway in organisms exposed to 

 toxicants are being developed by Weiss (1960). 

 This investigator cites similar work of Hosein 

 who has found that a shift in a metabolic pathway 

 was affected, leading to an increased production 

 of carnitine, which accumulates in the brain and 

 interferes with nerve function, resulting in con- 

 vulsive activity. 



The histopathological findings for the 

 fish exposed to DDT show close agreement with 

 the results of other workers using different test 

 animals and chlorinated hydrocarbons. Though 

 brain lesions have been seen in the cerebral 

 lobes in the dog (Kitselman, 1953) after aldrin 

 and dieldrin poisoning and sometimes in lamb 

 and poultry after aldrin poisoning (Baxter, 1959), 

 there are other cases cited by Baxter, in which 

 insecticide poisoning has not produced brain 

 lesions. This is true for sheep exposed to 

 dieldrin and occasionally for the lamb. The 

 absence of lesions also in the trout and guppy 

 forebrains indicates that brain lesions may not 

 be a significant cause of death in insecticide 

 poisoning. 



No histological studies of the intestine 

 of animals exposed to insecticides were found 

 in the literature, though Gowdey and Stravraky 

 (1955) mentioned that dieldrin and aldrin had 

 inhibitory effects on intestinal motility. The 

 severity of the intestinal lesions found in the 

 trout and guppies may have been a direct cause 

 of death in the fish by preventing the normal 

 digestion and assimilation of food. If the dis- 

 turbances in the intestine are an indirect cause 

 of death, through starvation, the insensitivity 

 of the trout to DDT before the yolk sacs are 

 resorbed could be explained. However, further 

 study is needed to determine whether the fish 

 are resistant because the mouth does not oper- 

 ate to bring water into the intestine at this 

 stage in development, thus preventing absorp- 

 tion of DDT into the blood stream (as suggested 

 by Mounts', or because a normally functioning 

 intestine is not needed while the yolk sac is still 

 present . 



Nelson e^aL., (1949) using DDD, Kitsel- 

 man (1953) using dieldrin and aldrin on dogs, and 

 Baxter (1959) studying effects of aldrin on lambs 

 all found moderate to severe fatty degeneration 

 in the liver after exposure to the insecticide. 

 The indications of degeneration in the lamb liver 

 were necrosis of the hepatic cells, accumulation 

 of refractile round bodies which looked similar 

 to vacuoles in hematoxylin -eosin, bleeding, and 

 general congestion. The liver in the dogs was 

 found in the severest cases to be quite foamy in 

 appearance. A more complete histological study 

 series of the test fish might reveal recovery 

 potential of necrotic livers and at what stage in 

 the necrotic process the swollen cells which 

 were seen in the trout liver appear. Waud (1952, 

 as reported by Gowdey^ al_., 1955) found that 

 the blood sugar of cats fed aldrin doubled and 

 that this level was even higher when convulsions 

 set in before death. The lethal dosage of DDT 

 given the guppies (.032 ppm) may have had a 

 similar effect, causing a complete conversion 

 of the stored glycogen in the liver to glucose . 



Bell (1961), Kitselman (1953), and Baxter 

 (1959), using different animals and insecticides 

 reported that chlorinated hydrocarbons caused 

 degeneration of the renal tubules . The severity 

 of degeneration varied with the animal and con- 

 centration and ranged from an increase in tubular 

 fat and slight hemorrhaging in the surrounding 

 tissue to eventual occlusion of the tubules with 

 debris and sloughing of necrotic epithelium into 

 the lumen. Although there was no noticeable 

 fatty degeneration in the tubules of the trout or 

 guppies, marked necrosis of the epithelium had 

 occurred in many of the trout fry tubules after 

 two weeks . 



Though both interrenal and chromatin cells 

 of the adrenal gland are scattered in the bony 

 fish, both were seen best in the whorls of epithe- 

 lial cells in the kidney of both the trout and guppy. 

 Degeneration of this tissue in the fish was indica- 

 tive that the adrenal tissue was directly affected 

 by the DDT. 



The role of the adrenal gland in the ef- 

 fects of DDT on an organism is implicated in 



9/ See footnote 4. 



13 



