Polymorphisms of the bovine luteinizing hormone/choriogonadotropin receptor (LHCGR) gene and its association with ovarian follicular cystsZ

Luteinizing hormone chorionic gonadotropin (LHCGR) gene affects the functionality of the reproductive axis. It has been reported that the mutation of the LHCGR is associated with ovarian failure. The aims of this study were: a) verifying the probable existing polymorphism of LHCGR gene using single-stranded conformation polymorphism (SSCP) technique and b) comparision of the luteinizing hormone (LH) and 17-beta estradiolconcentrations between cystic follicular cows (CFC) and healthy cows in Holstein dairy cattle. Blood samples were taken from healthy (n=31) and CFC(n=31) cows. The ovarian cyst status had been distinguished by an expert veterinarian. DNA was extracted from blood cells by chloroform-iso amyl alcohol method. A 261 bp fragment of LHCGR gene was amplified using PCR. The PCR products were used for SSCP technique. Logistic regression analysis was applied to find genotype frequencies in relationship in CFC and healthy animals. The frequencies of AA and BB genotypes were 28.57% and 3.17% in CFC, 6.35% and 31.75% in healthy cows, respectively. It was concluded that both AA and BB genotypes have a significant relationship with status of ovarian cysts (p<0.001). In CFC with AA genotype, the 17-beta estradiol level was significantly higher than healthy ones (p<0.05). LH level in healthy and CFC group was 4.45 +/- 0.4, and 3.14 +/- 0.2 ng/ml, respectively. Furthermore, the level of 17-beta estradiol level in CFC group (7.77 +/- 2.23 pg/ml) was significantly higher than healthy group (5.116 +/- 1.02 pg/ml). Our study demonstrates that LHCGR, the candidate gene described for cysticovarian follicles (COF), may participate in the pathophysiology of COF in Holstein cows. In other words, LHCGR gene polymorphism is associated with incidence of ovarian cysts. In practice we suggest that LHCGR gene could be utilized in selection of candidate animals for breeding.