title: Immunolocalization of insulin-like growth factor-I (IGF-I) and its receptors (IGF-IR) in the equine epididymis.
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.
authors.forename: Minjung
authors.initials: M
authors.lastname: Yoon
authors.forename: Juliann
authors.initials: J
authors.lastname: Jiang
authors.forename: Ki Hwa
authors.initials: KH
authors.lastname: Chung
authors.forename: Janet Fay
authors.initials: JF
authors.lastname: Roser
mesh_terms: D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D004822:Epididymis / Q000378:metabolism; D006736:Horses; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D013997:Time Factors
chemical_list: D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1