Plasma pyroglutamic acid levels after oral administration of monosodium glutamate to human volunteers.

Plasma levels of pyroglutamic (PY) and glutamic (GA) acids have been measured after oral administration of monosodium glutamate (MSG) to 6 human volunteers. MSG (43 mg/kg) was administered either after an overnight fast or immediately after a normal meal. In fasting subjects plasma GA peak levels were about 2.3 times the basal levels whereas the increase in plasma PY levels were only 1.5-fold. When MSG was administered with a meal plasma GA levels were raised, to a lesser extent, while no increase could be observed in plasma PY.