LEVELS OF TAURINE, AMINO-ACIDS AND RELATED-COMPOUNDS IN PLASMA, VENA-CAVA, AORTA AND HEART OF RATS AFTER TAURINE ADMINISTRATION

A pharmacokinetic study on the fate of administered taurine in blood a nd some tissues and the effects on other amino compounds is presented. Injection of taurine (0.8 g/kg i.p.) causes markedly elevated plasma levels (70-fold at 15 min) which decrease later and approach baseline values after about 4 h. Concomitantly, other plasma amino compounds su ch as ornithine, threonine, asparagine, glutamine, alanine, citrulline , tyrosine, tryptophan, glycine, ammonia and arginine are reduced, whe reas beta-alanine and phosphoserine are increased. At 30 min, tissue l evels of taurine are roughly doubled in the vena cava and heart and tr ipled in the aorta. Other amino compounds affected are aspartic acid, serine, valine, methionine, tyrosine, ammonia, lysine, histidine, and arginine in the vena cava; aspartic acid, reduced glutathione, serine, and ammonia in the aorta; and reduced glutathione, alanine, citrullin e and methionine in the heart. In most of these cases, plasma changes do not predict tissue changes which are generally substance- and tissu e-specific. Thus, pharmacological effects seen after taurine administr ation could be caused by elevated taurine levels per se and/or taurine -induced changes in some of the amino acids and related compounds.