Cloning of glycoprotein hormone alfa subunit in pejerrey Odontesthes bonariensis. expression profile of Gonadotropin subunits and relationship with GnRHs expression and plasma sex steroid levels in males.

MIRANDA, L.A.; STRÜSSMANN, C.A.; GUILGUR, L.G.; STROBL-MAZZULLA, P.H.; SOMOZA, G.M.

Buenos Aires, Argentina.

Jornada; VIII Jornadas Multidisciplinarias de la Sociedad Argentina de Biología.; 2006

In the present work the cDNA encoding pejerrey glycoprotein hormone alfa subunit (pjGPH-a) was cloned and characterized. Also, pituitary expression of pejerrey gonadotropin subunits (pjFSH-b, pjLH-b and pjGPH-a) was analyzed by real time PCR and compared to brain expression of endogenous GnRHs (sGnRH, pjGnRH and cGnRH-II) and plasma sex steroid levels in adult pejerrey males. The nucleotide sequence of pjGPH-a consisted of 677 bp containing the open reading frame of 366 bp. The signal and the mature peptide were estimated to have 23 and 98 aa respectively, and as in other teleost species. This protein has 10 cys residues and 2 potential N-glycosilation sites at Asn 55 and Asn 80. The aa sequence of pjGPH-a mature peptide was compared with other teleost fihes GPH-a sequence showing the highest homology (80,5%) with a percifirm fishes. Expression results showed that maturing male had high levels of pjFSH-b and pjGPH-a subunits, and intermediate levels of pjLH-b when compared with running ripe and spent stages. These animals had the lowest plasma T and 11KT values as well as low expression of sGnRH, pjGnRH and cGnRH-II. Running ripe male had the lowest expression of pjFSH-b and the highest expression of pjLH-b and pjGPH-a subunits, and of the three GnRHs genes. At this stage, it was observed the highest values of T and 11KT. Spent males showed low expression of the three GtHs subunits, sGnRH, pjGnRJ and low levels of T. At this stage, 11KT levels and cGnRH-II expression showed a tendency to decrease both the values were not statistically significant to running ripe state. The present result would suggest that T and 11KT modulate the expression of the pjFSH subunits. The expression of the anterior brain GnRH variants, sGnRH and pjGnRH is correlated with pjLH-b expression and reinforce the importance of the forebrain GnRH variants on the regulation of the pituitary function.