TY - JOUR
T1 - Elevated concentrations and synthetic pathways of trimethylamine oxide and urea in some teleost fishes of McMurdo Sound, Antarctica
AU - Raymond, J. A.
AU - DeVries, A. L.
N1 - Funding Information:
We thank students V. Valentin, L. Gallofin, and M. Waffle for conducting the TMAO, urea and enzyme assays, Dr. A. Bencsath, (Univ. S. Alabama) for the mass spectroscopy analyses, D. Laird (Stanford Univ.) for assistance in providing the samples from Brabant Is., and Dr. P. Yancey for pointing out helpful references. This research was supported by NSF grants DPP9123228 and OPP9423920 to J.R. and OPP9615023 to A.D.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1998
Y1 - 1998
N2 - Levels of trimethylamine oxide (TMAO) and urea in various tissues of several teleost fishes of McMurdo Sound, Antarctica were determined. TMAO levels in muscle tended to be high, with levels in several species exceeding 140 mM kg-1 wet weight. The high levels appear to be necessary to osmotically balance high levels of sodium and chloride in the blood of these species. In two species (Dissostichus mawsoni and Gymnodraco acuticeps), significant levels of TMAO (> 80 mM l-1) were also found in the blood, while virtually no TMAO was found in the blood of a related, temperate water species. In other Antarctic species, serum TMAO levels varied from moderate to low levels. Urea levels in several species were in the range 15-25 mM l-1, which is higher than those in temperate water fishes. The high TMAO and urea levels make important contributions to the fishes' high osmolarities, and thus help to lower freezing points. These data are consistent with previous data obtained from some northern fishes. Fishes with high serum TMAO levels had liver TMAase activity whereas those with no serum TMAO did not. Activity levels of uricolytic enzymes in D. mawsoni and G. acuticeps were not noticeably different from those of temperate water fishes. These species showed moderate to high activities of three ornithine urea cycle enzymes (CPS, OCT and arginase) but low activity of the argininosuccinate synthetase/argininosuccinyl lyase system. These data suggest that a dietary arginine/arginase system is an important source of urea in these species.
AB - Levels of trimethylamine oxide (TMAO) and urea in various tissues of several teleost fishes of McMurdo Sound, Antarctica were determined. TMAO levels in muscle tended to be high, with levels in several species exceeding 140 mM kg-1 wet weight. The high levels appear to be necessary to osmotically balance high levels of sodium and chloride in the blood of these species. In two species (Dissostichus mawsoni and Gymnodraco acuticeps), significant levels of TMAO (> 80 mM l-1) were also found in the blood, while virtually no TMAO was found in the blood of a related, temperate water species. In other Antarctic species, serum TMAO levels varied from moderate to low levels. Urea levels in several species were in the range 15-25 mM l-1, which is higher than those in temperate water fishes. The high TMAO and urea levels make important contributions to the fishes' high osmolarities, and thus help to lower freezing points. These data are consistent with previous data obtained from some northern fishes. Fishes with high serum TMAO levels had liver TMAase activity whereas those with no serum TMAO did not. Activity levels of uricolytic enzymes in D. mawsoni and G. acuticeps were not noticeably different from those of temperate water fishes. These species showed moderate to high activities of three ornithine urea cycle enzymes (CPS, OCT and arginase) but low activity of the argininosuccinate synthetase/argininosuccinyl lyase system. These data suggest that a dietary arginine/arginase system is an important source of urea in these species.
KW - Antarctica
KW - Cold adaptation
KW - Ornithine urea cycle
KW - TMAase
KW - Teleost fishes
KW - Trimethylamine oxide
KW - Urea
KW - Uricolysis
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U2 - 10.1023/A:1007778728627
DO - 10.1023/A:1007778728627
M3 - Article
AN - SCOPUS:0001002611
SN - 0920-1742
VL - 18
SP - 387
EP - 398
JO - Fish Physiology and Biochemistry
JF - Fish Physiology and Biochemistry
IS - 4
ER -