Urea content and urea production via the ornithine-urea cycle pathway during the ontogenic development of two teleost fishes

Guppies, toadfish, lungfish, coelacanths and frogs: a scenario for the evolution of urea retention in fishes

“…The arginine synthetic system that was nutritionally functional in agnathan larvae might then be subverted to generate arginine for urea synthesis. The data of Depeche et al (1979) who found a buildup of urea levels and urea synthetic capacity in guppies and trout embryos provide substantiation for our hypothesis that urea synthesis plays a significant role in the embryonic development of gnathostome fishes. The extension of the study of Depeche et al (1979) on the ontogenic development of urea levels and ureogenetic capacity to other fishes of diverse phylogeny and developmental type would, of course, serve as a test of our hypothesis.…”

Guppies, toadfish, lungfish, coelacanths and frogs: a scenario for the evolution of urea retention in fishes

“…The arginine synthetic system that was nutritionally functional in agnathan larvae might then be subverted to generate arginine for urea synthesis. The data of Depeche et al (1979) who found a buildup of urea levels and urea synthetic capacity in guppies and trout embryos provide substantiation for our hypothesis that urea synthesis plays a significant role in the embryonic development of gnathostome fishes. The extension of the study of Depeche et al (1979) on the ontogenic development of urea levels and ureogenetic capacity to other fishes of diverse phylogeny and developmental type would, of course, serve as a test of our hypothesis.…”

Expression of Carbamoyl-phosphate Synthetase III mRNA during the Early Stages of Development and in Muscle of Adult Rainbow Trout (Oncorhynchus mykiss)

“…3 However, we have recently shown that ornithine carbamoyltransferase and CPSase III activities are induced during early life stages, induction beginning at hatch, reaching a peak at 60 days post-fertilization, and then declining (11). These results together with other studies have suggested that expression of CPSase III and the urea cycle during early life stages may be characteristic for all ammonotelic teleosts, the function perhaps being related to detoxification of ammonia and/or osmoregulation (9,11,26). The study by Wright et al (11) showed that urea was synthesized early in embryonic development, but that CPSase III activity was not detected until after hatch.…”

Protein and arginine requirements for maintenance and nitrogen gain in four teleosts

“…Huggins et al (1969) detected all enzymes of the OUC in the liver of a number of teleosts. Dépêche et al (1979) showed urea production by the OUC in juvenile trout but not in bigger fish. Cowey & Walton (1989) detected only low activities of the OUC enzymes.…”

Guppies, toadfish, lungfish, coelacanths and frogs: a scenario for the evolution of urea retention in fishes

“…The arginine synthetic system that was nutritionally functional in agnathan larvae might then be subverted to generate arginine for urea synthesis. The data of Depeche et al (1979) who found a buildup of urea levels and urea synthetic capacity in guppies and trout embryos provide substantiation for our hypothesis that urea synthesis plays a significant role in the embryonic development of gnathostome fishes. The extension of the study of Depeche et al (1979) on the ontogenic development of urea levels and ureogenetic capacity to other fishes of diverse phylogeny and developmental type would, of course, serve as a test of our hypothesis.…”

Expression of Carbamoyl-phosphate Synthetase III mRNA during the Early Stages of Development and in Muscle of Adult Rainbow Trout (Oncorhynchus mykiss)

“…3 However, we have recently shown that ornithine carbamoyltransferase and CPSase III activities are induced during early life stages, induction beginning at hatch, reaching a peak at 60 days post-fertilization, and then declining (11). These results together with other studies have suggested that expression of CPSase III and the urea cycle during early life stages may be characteristic for all ammonotelic teleosts, the function perhaps being related to detoxification of ammonia and/or osmoregulation (9,11,26). The study by Wright et al (11) showed that urea was synthesized early in embryonic development, but that CPSase III activity was not detected until after hatch.…”

Protein and arginine requirements for maintenance and nitrogen gain in four teleosts

“…Huggins et al (1969) detected all enzymes of the OUC in the liver of a number of teleosts. Dépêche et al (1979) showed urea production by the OUC in juvenile trout but not in bigger fish. Cowey & Walton (1989) detected only low activities of the OUC enzymes.…”

Guppies, toadfish, lungfish, coelacanths and frogs: a scenario for the evolution of urea retention in fishes

“…The arginine synthetic system that was nutritionally functional in agnathan larvae might then be subverted to generate arginine for urea synthesis. The data of Depeche et al (1979) who found a buildup of urea levels and urea synthetic capacity in guppies and trout embryos provide substantiation for our hypothesis that urea synthesis plays a significant role in the embryonic development of gnathostome fishes. The extension of the study of Depeche et al (1979) on the ontogenic development of urea levels and ureogenetic capacity to other fishes of diverse phylogeny and developmental type would, of course, serve as a test of our hypothesis.…”

Expression of Carbamoyl-phosphate Synthetase III mRNA during the Early Stages of Development and in Muscle of Adult Rainbow Trout (Oncorhynchus mykiss)

“…3 However, we have recently shown that ornithine carbamoyltransferase and CPSase III activities are induced during early life stages, induction beginning at hatch, reaching a peak at 60 days post-fertilization, and then declining (11). These results together with other studies have suggested that expression of CPSase III and the urea cycle during early life stages may be characteristic for all ammonotelic teleosts, the function perhaps being related to detoxification of ammonia and/or osmoregulation (9,11,26). The study by Wright et al (11) showed that urea was synthesized early in embryonic development, but that CPSase III activity was not detected until after hatch.…”

Protein and arginine requirements for maintenance and nitrogen gain in four teleosts

“…Huggins et al (1969) detected all enzymes of the OUC in the liver of a number of teleosts. Dépêche et al (1979) showed urea production by the OUC in juvenile trout but not in bigger fish. Cowey & Walton (1989) detected only low activities of the OUC enzymes.…”