“…The putative precursor of brain y-hydroxybutyrate is y-aminobutyrate (Roth and Giarman, 1969), even though it has been shown that 1,4butanediol can also be oxidized to y-hydroxybutyrate (Roth and Giarman, 1968). Neither of these compounds is a likely candidate for the role of precursor of extraneural y-hydroxybutyrate inasmuch as 1,4-butanediol has only tentatively been demonstrated in trace quantities in rat liver (Bergelson et al, 1966), and the y-aminobutyrate concentration, at least in kidney and liver, is less than 1% of its concentration in brain (Drummond and Phillips, 1974).…”