Molecular Cloning And Tissue Expression Analysis Of Goose VIP And VIPR MRNA Throughout The Reproductive Cycle

Vasoactive Itestinal Peptide(VIP) is well known as a major plactin(PRL) releasing factor in avian species, whose activity is believed to be mediated by a specific VIP receptor(VIPR) located on the surface membranes of cells. In the present study, goose VIP gene complete CDS and VIPR gene partial CDS were cloned and its mRNA abundance was quantified in various tissues during different reproductive stages by real-time PCR. In addition, goose plasma PRL concentration was measured acrosing different reproductive cycle using radioimmunoassay.The nucleotide sequences of goose VIP gene and VIPR gene fragments share approximately 95% and 94% similarity with chicken VIP gene and VIPR gene, respectively. The RT-PCR amplificatory products of goose VIP and VIPR were found in various tissues throughout reproductive cycle, the lavels of VIP mRNA in the intestine, hypothalamus and pancreas are significantly higher than other tissues(P<0.01), however, the abundance of VIPR mRNA in the intestine, pituitary gland, lung and pancreas are higher than other tissues(P<0.05). In hypothalamus, the highest levels of mRNA for the VIP were observed in the incubating period goose(P<0.01), steady-state levels of mRNA for the VIP were found to be lowest in the reproductively inactive goose(P<0.01). In the other tissue, the highest levels of mRNA for the VIP were observed in the laying and photostimulated goose(P<0.01), stesdy-state levels of mRNA for the VIP were found to be lowest in the reproductively inactive goose(P<0.01). Relatively high steady-state levels of goose pituitary VIPR mRNA were found in incubating period compared to the other reproductive stages, in following reproductively inactive period, the levels of pituitary goose VIPR mRNA were detected to be lowest(P<0.01). The levels of goose uterine tube VIPR mRNA expression were investigated to be highest in the incabuting period and photorefratory goose(P<0.01), the mRNA expression of goose uterine tube VIPR was obviously lower in the laying, reproductively inactive and photostimulated goose compare with incabuting period and photorefratory goose(P<0.01). In other tissues, the steady-state levels of goose VIPR were dramatically lowest in the reproductively inactive goose(P<0.01), in addition, it vas not significantly different in the other reproductive stage(P> 0.05). Interestingly, the abundance of goose lung VIPR mRNA was remankable higher than other tissues. Goose plasma PRL concentration varied with the changement of reproductively cycle. The PRL mean for the plasma samples in the incubating group were considerably greatest in all tested groups(33.52±6.55 ng/ml)(P<0.01), whereas plasma PRL concentration in the reproductively inactive group were lowest(8.03±2.36 ng/ml) (P<0.01).In summary, goose VIP expression in hypothalamus and VIPR expression in pituitary is markedly involved with PRL secretion. The data also suggests that prominent role that VIP plays in goose reproductive cycle is regulated through VIPR gene expression in pituitary.