[Metabolism and catabolism to CO2 of [14C] gamma-aminobutyric acid conjugates with pyridoxal phosphate, nicotinate and biotin].

Pharmacokinetics and catabolism to CO2 in the mice organism and metabolic transformation by the tissues homogenates of [1-14C] GABA and its conjugates with nicotinate, pyridoxal phosphate and biotin have been studied. The permeability of nicotinoyl-GABA through the hemato-encephalic barrier was 10 times as much as the corresponding value for GABA and its conjugates with other vitamins. PLP-GABA is eliminated more rapidly from the brain in comparison with GABA, biotinyl-GABA is retained to a higher degree in kidneys, the entero-hepatic recycling takes place more actively for nicotinoyl-GABA. The latter, in contrast to biotinyl-GABA, remains unaffected by the liver, intestine mucose membrane and brain proteases and is catabolized to CO2 to a considerably lower extent as compared with GABA, perhaps due to the intestine bacterial microflora.