N-Acetylation of serotonin, octopamine and dopamine by adult Brugia pahangi

Abstract

The metabolism of biogenic amines by the filarial worm, Brugia pahangi, was investigated by incubating cut worms with radio-labelled amine substrates. Two-dimensional thin-layer chromatography and analysis on two high-performance liquid chromatography systems showed that [ 14C]5-hydroxytryptamine was metabolised to a less polar compound that was identified as N-acetyl 5-hydroxytryptamine. N-Acetyloctopamine and N-acetyldopamine were also formed when cut B. pahangi were incubated with [ 14C]octopamine and [ 3H]dopamine, respectively. N-Acetyltransferase activity towards 5-hydroxytryptamine was readily detected in nematode homogenates. This enzyme was localised in a 50 000 × g supernatant and required the addition of the co-substrate, acetyl CoA, for activity. No evidence was obtained for the involvement of monoamine oxidases in the metabolism of 5-HT in these filarial worms.