Technical Abstract: Dietary glutamate (GLU) is extensively metabolized as a major gut oxidative fuel when consumed at a normal dietary intake. Given that monosodium glutamate is often added to prepared foods, our aim was to quantify the metabolic fate of excessive dietary GLU intake. Piglets (28-d-old) were implanted with carotid artery, jugular vein, portal vein and duodenal catheters and an ultrasonic flow probe on the portal vein. Piglets were fed a constant, intraduodenal, milk-based, formula infusion with GLU at 100%, 300%, 400%, or 500% of the normal dietary GLU intake (425(mol x kg-1 x h-1) for 4 h. Pigs (N=12) fed 100% and 400% dietary GLU intake received an intravenous and intraduodenal infusion of U-13C-GLU on separate days. Arterial concentration, net portal absorption, and net portal utilization of GLU were linearly increased with increasing dietary GLU intake. However, fractional net portal GLU utilization rates were similar at all dietary GLU intakes (~15-20% intake). First-pass, splanchnic utilization of dietary GLU was 97% and 88% of intake at 100% and 400% dietary GLU, and preferentially metabolized by gut rather than the liver. Fractional gut oxidation of enteral GLU to CO2 was 49% and 33% at the 100% and 400% dietary GLU intake. We conclude that the gut is capable of extensive glutamate metabolism even with dietary intakes 3 to 5-fold higher than normal. (Supported by International Glutamate Technical Committee).