Expression level of Ghrelin and GHSR mRNA in testis of cattle-yak and yak

The expression level of Ghrelin and growth hormone secretagogue receptor（GHSR） gene mRNA tested respectively in testis of cattle-yak and yak by using fluorescence quantitative polymerase chain reaction （PCR）. The results showed that Ghrelin mRNA expression level in cattle-yak testis was significantly higher than that in yak（ 0.8177±0.0225，0.4656±0.0222，P ＜ 0.05）. Similarly，GHSR mRNA expression level in cattleyak testis was significantly higher than that in yak（0.8622±0.0347，0.4722±0.0761，P ＜ 0.05）. These results indicated that both Ghrelin and GHSR mRNA expression level in cattle-yak testis was significantly higher than that in yak，which was likely to be one of the reasons for male infertility of cattle-yak.