Olfactory receptors (OR) are primarily responsible for the detection of odorant molecules. We previously demonstrated that OR7D4, an OR for androstenone, is expressed in the vomeronasal organ and olfactory epithelium tissue of stallions. Recently, the expression of OR1I1 in the human testes was reported and the possible roles of OR1I1 in the testicular cells were suggested. The objectives of this study were 1) to explore the expression of OR7D4 and OR1I1 in stallion testes, and 2) to define the specific localization of OR7D4 and OR1I1 in the testicular tissues. Stallion testicular tissue samples were used for this study. Western blot was performed to confirm the cross-reactivity of OR7D4 and OR1I1 antibody with stallion testicular tissue samples. OR7D4 and OR1I1 gene expressions were investigated using reverse transcriptionpolymerase chain reaction (RT-PCR) in stallion testes. Immunofluorescence was performed to investigate the expression of OR7D4 and OR1I1 in stallion testicular tissues. The protein bands for OR7D4 and OR1I1 from the testes were observed at approximately 38 kDa and 43 kDa, respectively. The mRNA of OR7D4 and OR1I1 were detected in stallion testes. Immunolabeling of OR7D4 and OR1I1 in the cytoplasm of both spermatogonia and Leydig cells was observed. In conclusion, androstenone and another odorant chemical, which is recognized by OR1I1, may play an important role in stallion testes.

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSION
REFERENCES

• Junyoung Kim(Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 37224, Korea)
• Youngwook Jung(Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 37224, Korea)
• Heejun Jung(Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 37224, Korea)
• Muhammad Shakeel(Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 37224, Korea)
• Minjung Yoon(Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 37224, Korea) Corresponding author