Evaluation of Reproductive Activity and Hormonal Profiles (Prolactin and Inhibin Beta-A) in Association with Polymorphisms in the Prolactin Receptor and Inhibin Beta A Genes in Arabian Mares
DOI:
https://doi.org/10.48165/ijapm.2026.42.1.12Keywords:
Arabian mares, Prolactin, Inhibin, Receptor, Gene, PolymorphismAbstract
This study investigated the relationship between reproductive activity, hormonal profiles (prolactin and inhibin Beta-A), and genetic variations in the prolactin receptor (PRLR) and inhibin beta A (INHBA) genes in Arabian mares. Ten Arabian mares were classified as either true polyestrus (Group A, n=6 mares), exhibiting estrous cycles around the year, or seasonal polyestrus mares (Group B, n=4), that exhibiting winter anestrus, fall, and Spring transitional periods. Blood samples were collected for hormone analysis by using radioimmunoassay (RIA) and for DNA extraction and gene sequencing. The Results of this study showed seasonal variations in prolactin and inhibin beta-A levels. Group B mares exhibited significantly lower inhibin Beta-A levels during winter compared with the other seasons and compared to Group A mares during winter, consistent with anestrus (deep and estrum). No polymorphisms were found in the sequenced region of the inhibin beta-A gene (INHBA); Two single nucleotide polymorphisms (SNPs) were identified in the prolactin gene (PRLR). Mares with the A/A genotype for SNP1 had significantly higher prolactin concentration than mares with the A/G genotype (P=0.0084). Mares showing the T/T genotype for SNP2 exhibited elevated prolactin levels compared to those with the G/T genotype. These results indicate a possible association between PRLR gene polymorphisms and prolactin levels that affect the reproductive seasonality seen in Arabian mares.References
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