Our results show for first time in fish a differential response of PRP-PACAP transcripts to dietary manipulations, and confirm the sensitivity of the pejerrey GH-IGF system to changes in diet composition despite the lack of (or in advance to) a clear response of somatic growth..     ///    "Regulation of somatic growth and gene expression of the GH-IGF system and PRP-PACAP by dietary lipid level in early juveniles of a teleost fish, the pejerrey (Odontesthes bonariensis).. "    ///    "These results in combination with the lower expression of the anorexigenic PRP-PACAP in fish fed diet L21 and the correlation analysis evidencing a particularly fine tuning of the GH-IGF system in group L13, suggest that this diet may cover the energy demands for growing pejerrey from 27?dah onwards. "    ///    "First, the full sequence of pejerrey PRP-PACAP was obtained by RT-PCR, using primers based on conserved fragments of teleosts PACAP sequences. "    ///    "Conversely, PRP-PACAP expression significantly decreased with increasing dietary lipids (L10?>?L21). "