Search

1. 1. Intraperitoneal LD 50 and LD 99·9 values for ammonium acetate were determined in three species of ammonotelic fishes; rainbow trout ( Salmo gairdnerii ), channel catfish ( Ictalurus punctatus ) and goldfish ( Carassius auratus ). 2. 2. There was a direct relationship between the LD 50 values for ammonium acetate and the relative resistance to environmental conditions, i.e. the trout were the most sensitive, the channel catfish intermediate and the goldfish quite resistant. 3. 3. An increase in aquarium temperature considerably decreased the fishes tolerance to the injected ammonium acetate. 4. 4. Fishes being ammonotelic were found to be more tolerant to the intraperitoneally administered ammonium acetate than either the ureotelic or uricotelic species (Wilson et al. , 1968). 5. 5. Several factors which may contribute to the higher tolerance of exogenous ammonia in the fishes are discussed.

1. 1. Intravenous and intraperitoneal ld 50 and ld 99·9 values for ammonium acetate were determined in a uricotelic species ( Gallus domesticus ) and in a ureotelic species ( Mus musculus ). 2. 2. The intravenous ld 50 and ld 99·9 values were 2·72 ± 0·101 and 4·87 ± 0·101 m-mole/kg body weight for chicks and 5·64 ± 0·083 and 7·67 ± 0·083 m-mole/kg body weight for mice. 3. 3. The intraperitoneal ld 50 and ld 99·9 values were 10·44 ± 0·405 and 26·2 ± 0·405 m-mole/kg body weight for chicks and 10·84 ± 0·203 and 18·0 ± 0·203 m-mole/kg body weight for mice. 4. 4. Intravenously, the ammonium acetate was twice as toxic in the chick as in the mouse, indicating in the chick a critical organ more sensitive to the ammonium ion. 5. 5. Intraperitoneally, the ammonium acetate did not differ significantly in tolerance by mice and chicks, indicating that in the avian liver some other pathway may be as efficient for detoxifing exogenous ammonia as the urea cycle in the mouse liver.

1. 1. The possible protective effect of some sodium salts of metabolizable acids against ammonia intoxication in chicks (Gallus domesticus) has been investigated. 2. 2. The following compounds were shown to exert a significant protective effect against ammonia intoxication in the chick when administered intraperitoneally 1 hr prior to the ammonia challenge: 2, 3 and 4 m-moles/kg sodium acetate; 3 m-moles/kg sodium propionate; 3 m-moles/kg sodium butyrate; 3 m-moles/kg sodium bicarbonate; and 3 m-moles/kg potassium acetate. These compounds did not have a comparable effect in mice (Mus musculus). 3. 3. Evidence is presented which indicates that the sodium ion of the metabolizable sodium salts exerts its effect by enhancing uric acid transport or excretion.