Sex difference in the turnover of GABA in the rat substantia nigra.

The turnover of GABA (estimated from the post-mortem accumulation of GABA), and the activity of glutamic acid decarboxylase and GABA transaminase, along with the saturation of both enzymes by cofactor pyridoxal phosphate, were studied in the substantia nigra of rats of both sexes. Although no sex differences were found in the in vitro measured characteristics of both enzymes involved in GABA metabolism, the turnover of GABA was greater in males. This finding is consistent with our previous reports showing the greater resistance of male rats to GABA-related convulsions.