Functional insulin‐like factor 3 (INSL3) hormone‐receptor system in the testes and spermatozoa of domestic ruminants and its potential as a predictor of sire fertility |
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| Authors: | Ali M Pitia Kyoko Uchiyama Hiroaki Sano Masashi Kinukawa Yoshiaki Minato Hiroshi Sasada Tetsuya Kohsaka |
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| Affiliation: | 1. Division of Animal Resource Production, United Graduate School of Agricultural Science, Gifu University, Gifu, Japan;2. Laboratory of Animal Reproduction and Physiology, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan;3. Division of Animal Reproduction, Maebashi Institute of Animal Science, Livestock Improvement Association of Japan (LIAJ), Maebashi, Japan;4. Department of Animal Science, Faculty of Agriculture, Iwate University, Morioka, Japan;5. Laboratory of Animal Reproduction, School of Veterinary Medicine, Kitasato University, Towada, Japan |
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| Abstract: | Insulin‐like factor 3 (INSL3) is essential for fetal testis descent, and has been implicated in the testicular and sperm functions in adult males; however, similar functions in domestic ruminants remain largely unknown. This study investigated the functional INSL3 hormone‐receptor system in adult ruminant testes and spermatozoa, and explored its potential to diagnose the fertility of sires. Testes and spermatozoa were obtained from fertile bulls, rams and he‐goats, whereas subfertile testes and spermatozoa were obtained only from bulls. As expected, INSL3 was visualized in Leydig cells, while we clearly demonstrated that the functional receptor, relaxin family peptide receptor 2 (RXFP2), enabling INSL3 to bind was identified in testicular germ cells and in the sperm equatorial segment of bulls, rams and he‐goats. In comparison to fertile bulls, the percentage of INSL3‐ and RXFP2‐expressing cells and their expression levels per cell were significantly reduced in the testes of subfertile bulls. In addition, the population of INSL3‐binding spermatozoa was also significantly reduced in the semen of subfertile bulls. These results provide evidence for a functional INSL3 hormone‐receptor system operating in ruminant testes and spermatozoa, and its potential to predict subfertility in sires. |
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| Keywords: | domestic ruminants INSL3 RXFP2 spermatozoa testis |
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