Stimulation of L-ornithine uptake and L-citrulline and urea biosynthesis by D-arginine.
The action of D-arginine on isolated cells and mitochondria obtained from rat liver was studied. The D-amino acid at 200 microM stimulated by 40% the rate of urea biosynthesis by isolated hepatocytes. Citrulline formation was increased 60-70% in rat liver mitochondria incubated with 10 microM D-arginine. In these mitochondria, ornithine uptake was enhanced 204% with 1 microM D-arginine. Inhibition in urea and citrulline synthesis and in ornithine uptake was recorded with high concentrations of the D-amino acid. Respiratory control in liver mitochondria with glutamate-malate was inhibited 32% by 100 microM D-arginine. In isolated mitochondria loaded with Fluo-3-acetoxymethyl (AM) ester, 50 microM D-arginine diminished the matrix free calcium concentration.
Departamento de Bioquímica, Facultad de Medicina, U.N.A.M., México, D.F.
A
A
Saavedra-Molina
E
E
Piña
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D002956:Citrulline / Q000096:biosynthesis* / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D009952:Ornithine / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013050:Spectrometry, Fluorescence; D014508:Urea / Q000378:metabolism*
D002956:Citrulline; D000255:Adenosine Triphosphate; D014508:Urea; D001120:Arginine; D004492:Edetic Acid; D009952:Ornithine