METABOLISM OF AGMATINE INTO UREA BUT NOT INTO NITRIC-OXIDE IN RAT-BRAIN

AGMATINE is a guanidino compound abundant in bacteria and plants where it serves as a precursor for polyamine synthesis. It can interfere wi th several neurotransmission-related functions and can exert neuroprot ective effects after brain injury. Agmatine was recently identified in mammalian brain and its synthesis by arginine decarboxylation was cha racterized. Its metabolism by the brain is, however, unknown. Here we report evidence indicating that agmatine can be selectively metabolize d in the rat brain (cerebellum) into urea and thus, may lead to format ion of putrescine, the precursor of polyamine synthesis. In addition, while agmatine can inhibit brain nitric oxide synthase, it did not ser ve as a substrate for nitric oxide formation.