ABSTRACT
Monosodium glutamate (MSG) is a flavour enhancer that is used as a food additive (E621) in many parts of the world, especially in East Asian countries. However, in recent studies, it has been used as a neurotoxin because MSG is reported to cause neural degeneration in the hypothalamic arcuate of neonatal animals. The results of several studies show the negative effects of MSG injections on different parts of the hypothalamic-pituitary-gonadal (HPG) axis, in addition to its ability to inhibit secretion many reproductive neuropeptides, neurotrophic factors, and hormones, all of which play vital roles in the regulation of reproductive function. Oral administration or injection of large quantities of MSG into newborn animals results in a decrease in or overabundance of the production of many regulatory peptides of the male and female reproductive systems. In this review, we summarize the results of the most important studies that have examined the effect of oral consumption or injection of MSG on regulatory peptides of the HPG axis.