Urea cycle enzymes and glutamate dehydrogenase in Xenopus laevis and Bufo viridis adapted to high salinity.

Xenopus laevis was adapted stepwise to 600 m osmolar sodium chloride. After adaptation, the level of argininosuccinate lyase was raised 9-fold, carbamoylphosphate synthetase 6-fold, and ornithine carbamoyltransferase and arginase 3-fold. Liver glutamate dehydrogenase was also raised 5-fold; kidney glutamate dehydrogenase was unchanged. In Bufo viridis similarly adapted, there was a 5-fold increase in argininosuccinate lyase. When Xenopus laevis was adapted to 600 m osmolar sucrose, there was only an increase in argininosuccinate lyase, and that was only 2.4-fold. This indicates that the increases in urea cycle enzymes are at least in part responses to sodium chloride rather than just to osmotic stress.

[1]  U. Katz,et al.  Studies on the adaptation of the toad Bufo viridis to high salinities: oxygen consumption, plasma concentration and water content of the tissues. , 1973, The Journal of experimental biology.

[2]  L. Goldstein,et al.  Urea response to pure osmotic stress in the aquatic total Xenopus laevis. , 1973, The American journal of physiology.

[3]  P. Janssens.  The influence of ammonia on the transition to ureotelism in Xenopus laevis , 1972 .

[4]  H. F. Fisher,et al.  The binding of -ketoglutarate in a binary complex and in a ternary complex with NADP + by L-glutamate dehydrogenase. , 1972, Biochimica et biophysica acta.

[5]  L. Goldstein,et al.  Accelerated synthesis of urea in Xenopus laevis during osmotic stress. , 1970, The American journal of physiology.

[6]  L. Goldstein,et al.  Renal function during osmotic stress in the aquatic toad Xenopus laevis. , 1970, The American journal of physiology.

[7]  G. Shambaugh,et al.  Glutamate dehydrogenase biosynthesis in amphibian liver preparations. , 1970, The Journal of biological chemistry.

[8]  P. Cohen,et al.  Biosynthesis of urea in the estivating African lungfish and in Xenopus laevis under conditions of water-shortage. , 1968, Comparative biochemistry and physiology.

[9]  C. Coe,et al.  Amino acid metabolism and urea synthesis in naturally aestivating Xenopus laevis. , 1967, Comparative biochemistry and physiology.

[10]  M. Gordon.  INTRACELLULAR OSMOREGULATION IN SKELETAL MUSCLE DURING SALINITY ADAPTATION IN TWO SPECIES OF TOADS , 1965 .

[11]  E. Baldwin,et al.  Comparative studies of waste nitrogen metabolism in Amphibia. , 1962, The Biochemical journal.

[12]  M. Cragg,et al.  A comparative study of nitrogen excretion in some Amphibia and reptiles. , 1961, Comparative biochemistry and physiology.

[13]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[14]  S. S. Alexander,et al.  Experimental Studies On The Sexual Cycle Of The South African Clawed Toad (Xenopus Laevis). I , 1938 .