1,4-Butanediamine is an indicator of pollution-induced stress in higher plants: barley and rape stressed with Cr(III) or Cr(VI). 1,4-Butanediamine is an important source of GABA. In Vitro: 1,4-Butanediamine (Putrescine) is an important source of GABA in the postnatal rat subventricular zone. GABA synthesis from an alternative pathway uses 1,4-Butanediamine as a precursor.