AGMATINE, THE BACTERIAL AMINE, IS WIDELY DISTRIBUTED IN MAMMALIAN-TISSUES

We sought to determine whether agmatine (decarboxylated arginine), a b acterial product recently discovered for the first time in mammalian b rain, was contained in other organs. A method was developed for isolat ion of agmatine from tissue and detection by RP-HPLC following solid-l iquid extraction and derivatization with o-phthalaldehyde and mercapto ethanol. Recovery was about 80% and the limit of fluorometric detectio n was about 10 pg on column. In male Sprague-Dawley rats agmatine was unevenly and widely distributed in many tissues confirming its presenc e in mammals. The highest concentration (similar to 71 ng/mg wet weigh t) was found in stomach, with aorta and small intestine next, followed by smaller levels in spleen, adrenal, aorta, and skeletal muscle and brain. Serum concentrations were high. Agmatine in male Long Evans rat s of 3, 12, and 24 months of age demonstrated similar but not identica l tissue distribution without any effect of aging. Since agmatine bind s to alpha(2)-adrenergic and imidazoline receptors, is bioactive in a number of tissues, is contained in neurons and is found in serum and t issues, the findings are consistent with a potential role for agmatine as a neurotransmitter and/or hormone. It also raises the possibility that agmatine may, as in bacteria, serve as a polyamine precursor alon g metabolic pathways previously not detected in mammals.