Immunolocalization of insulin-like growth factor-I (IGF-I) and its receptors (IGF-IR) in the equine epididymis |
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| Authors: | Minjung YOON Juliann JIANG Ki Hwa CHUNG Janet Fay ROSER |
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| Institution: | 1)Department of Animal Science, University of California, Davis, CA 95616, USA;2)Department of Horse, Companion and Wild Animal Science, Kyungpook National University, Sangju, 742-711, Republic of Korea;3)Department of Animal Resources Technology, Gyeongnam National University of Science and Technology, Jinju, 660-758, Republic of Korea |
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| Abstract: | Insulin-like growth factor plays a paracrine/autocrine role in regulating testicular function in the stallion, but its presence in the equine epididymis remains unknown. The aim of this study was to test the hypothesis that insulin-like growth factor-I (IGF-I) and IGF-I receptor (IGF-IR) are localized in the caput, corpus, and cauda of the epididymis in an age-dependent manner. Immediately after castration, epididymal tissue was fixed, paraffin-embedded, and processed for immunohistochemistry (IHC). Western blot was also performed using equine epididymal extracts to verify the specificity of the antibodies against IGF-I and IGF-IR. Immunolabeling of IGF-I was observed in the cytoplasm of principal and basal cells in the caput, corpus, and cauda at the pre-pubertal (3–7 months), pubertal (12–18 months), post-pubertal (2–4 years), and adult stages (4.5–8 years). Immunolabeling of IGF-IR was observed in the cytoplasm of principal cells in all regions of the epididymis in
each age group. Immunolabeling of IGF-IR was also detected in the cytoplasm of basal cells from animals of all ages. Bands observed by Western blot corresponded to the molecular weights of IGF-I and IGF-IR, ~23 kDa and 95 kDa, respectively. These results suggest that IGF-I might function as an autocrine and/or paracrine factor during the development, maintenance and/or secretions of the stallion epididymis. |
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| Keywords: | Epididymis Immunohistochemistry (IHC) Insulin-like growth factor-I (IGF-I) IGF-I receptor (IGF-IR) Stallions |
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