Neuropeptide Y sequence and messenger RNA distribution in channel catfish (Ictalurus punctatus).

The action of neuropeptide Y (NPY) on food intake is of interest for the enhancement of growth of channel catfish (Ictalurus punctatus) for aquaculture. We sequenced 795 bp of complementary DNA (including 288 bp of open reading frame that encompassed the signal peptide, mature peptide, and carboxy-terminal peptide) from catfish brain NPY (GenBank accession number AF267164) and identified untranslated regions of the gene. We found high identity (88%-91%) of the amino acid sequence of the translated, mature protein with other fish NPYs. Using Northern blotting and reverse transcriptase polymerase chain reaction, we found NPY gene expression in the hypothalamus, myelencephalon, telencephalon, and optic tectum of the brain, but not the cerebellum or the pituitary gland. NPY expression was also found in immature ovary. Our results highlight the conserved nature of NPY in vertebrate systems, and the probes developed in this work will facilitate physiological and genetic studies of feeding and growth in channel catfish.