Characterization of pituitary adenyl cyclase activating polypeptide (PACAP) and growth hormone-releasing hormone (GHRH) in pejerrey (Odontesthes bonariensis).

KRAEMER MN; GOMEZ-REQUENI P; CANOSA LF

Ciudad Autonoma de Buenos Aires

Simposio; 7th Intrenational Symposium on Fish Endocrinology; 2012

Both PACAP and GHRH stimulate growth hormone (GH) secretion in teleost fish. The aim of this work was to characterize these peptide sequences in pejerrey (Odontesthes bonariensis) and to analyze their expression levels under different physiological conditions known to affect growth and/or GH secretion in fish. First, we have cloned the full length cDNA for pjPACAP and pjGHRH by RT-PCR and 3' and 5' RACE. Sequences of pjGHRH and pjPACAP yielded respectively 70% and 75% identity compared to other fish species. Both transcripts were expressed in the brain and pjGHRH mRNA was also expressed in the liver. In situ hybridization studies revealed pjPACAP expression in the dorsal and ventral areas of the telencephalon (TEL) and in the antero-ventral part and the diffuse nucleus of the inferior lobe (NDLI) of the hypothalamus (HYP) whereas pjGHRH was found in the olfactory bulb, the dorsal TEL, the preoptic area, the ventral and tuberal HYP and the NDIL. Estradiol administration (50μg/gr) significantly increased pjGHRH expression but had no effect on pjPACAP expression. Effects of water temperature and increasing dietary lipid content were also tested revealing a differential regulation which suggests differences in peptide functionality. Grants: PICT06-74, PICT10-1493, PIP271.