Oral and Subcutaneous Administration of Monosodium Glutamate to Infant Rodents and Dogs

Abstract

REPORTS by Olney¹ and Olney and Sharpe² implicate mono-sodium glutamate (MSG) as a specific central nervous system toxicant in infant animals. Within a few hours, subcutaneous and oral doses of between 0.5 and 5 g/kg body weight produced intracellular oedema and neuronal necrosis in the paramedian plane bordering on the roof and floor of the third ventricle. Preoptic and arcuate nuclei of the hypothalamus were reported to be selectively affected, as well as the scattered neurones within the median eminence (nuclei tuberales). In mice given similar doses of MSG in infancy and allowed to grow to maturity, excessive weight gains were reported after 60 days. The Olney studies and the inference of potential risk from the use of monosodium glutamate as a seasoning agent have been the subject of polemical communications^3–5 and are under review by a committee of the National Academy of Sciences—National Research Council.