Abstract: High ambient temperature has largely reduced the milk production due to the weak heat tolerance ability of Holstein. One potential mechanism for the destructive effect on organism is that the heat stress stimulated excessive cellular toxicants. The glutathione S-transferase Pi (GSTP1) has been proposed to play an important role to inactivate toxic metabolites in human malignant tumors. In this study, researchers evaluated the effect of heat stress on GSTP1 mRNA expression in Holstein using semi-quantitative RT-PCR method. With the liver tissue exception, the GSTP1 gene showed relatively high expression level in heart, spleen and kidney tissues in cool ambient temperature. After heat stress treatment, the GSTP1 mRNA expression increased significantly in all studied tissues. We sequenced the 3705 bp fragment containing complete sequence of GSTP1 gene among 15 cows and detected 31 variations. The nonsynonymous variation of G18C (p.M6I) was further scanned in 106 Holsteins using RFLP method to analyze the association of genotypes with heat tolerance ability. However, we did not detect statistical difference of heat tolerance ability among genotypes. To the knowledge, this is the first report to study GSTP1 mRNA expression under heat stress, SNPs distribution and association of genotypes with heat tolerance ability in Holstein. The significantly elevated expression of GSTP1 would suggest the positive role to resist heat stress, especially in liver tissue.
Jia Yao, Kun Liao, Qiu-Ling Li, Chang-Fa Wang, Hong-Mei Wang, Song-Jia Lai and Ji-Feng Zhong, 2011. mRNA Expression of Glutathione S-Transferase Pi (GSTP1) under Heat Stress and Association of Genotypes with Heat Tolerance Ability in Holstein. Journal of Animal and Veterinary Advances, 10: 757-763.