Sequencing downstream of the C-terminal exon 14 of the human noradrenaline transporter (hNAT) gene reveals 5 consensus polyadenylation signals, several adenylate/uridylate-rich elements (AREs) and a new C-terminal exon, designated as exon 15. The tandemly arranged polyadenylation sites are in good conformity with the 3.6- and 5.8-kb hNAT mRNA transcripts. Expression of the alternatively spliced C-terminal exon 15 is shown by RT-PCR. This alternative splicing event proposes additional hNAT mRNA species of 2.4-3 kb in size. Corresponding NAT transcripts are found by Northern analysis of human SKN and rat PC12 cell RNA. Sequence comparison of the hNAT gene to two bovine NAT cDNAs shows the interspecies conservation of this alternative splicing event, the close relationship of human and bovine NAT genes, and implicates a functional role for the transporters C-terminal domain.