Mean peak plasma
glutamate concentrations and area under the plasma
glutamate concentration-time curve are much lower in adult humans ingesting monosodium
L-glutamate (
MSG) in formula than in water. The present study investigated the effects of individual meal components on portal and vena caval plasma
glutamate concentration in young pigs administered
MSG. Portal vein
catheters and gastrojejunal tubes were placed in four young male pigs, and the animals were allowed to recover. Each animal was then administered four water solutions providing 500 mg/kg
body weight MSG in a Latin square design. One
solution provided only
MSG; the second provided
MSG and 1 g/kg
body weight metabolizable
carbohydrate (partially hydrolyzed corn
starch); the third provided
MSG and 1 g/kg
body weight nonmetabolizable
carbohydrate (beta-
cellobiose); and the fourth provided
MSG and 0.4 g/kg
body weight of an
amino acid mixture (
Aminosyn, Abbott Laboratories, North Chicago, Ill). Mean peak plasma
glutamate concentration and area under the plasma
glutamate concentration-time curve were significantly lower (P less than 0.05) in both portal and vena caval blood when
MSG was administered with metabolizable
carbohydrate than when administered in water. Simultaneous ingestion of
MSG with nonmetabolizable
carbohydrate (beta-
cellobiose) or
amino acids had no significant effect on either mean peak portal or vena caval plasma
glutamate concentration or area under the plasma
glutamate concentration-time curves when compared to values observed when
MSG was administered alone. The data suggest that metabolizable
carbohydrate is the meal component affecting plasma
glutamate concentration.