Immunohistochemical analysis of extracellular signal-regulated kinase expression in mature and immature bulls' testes and epididymides.

Abstract

Extracellular signal-regulated kinase (ERK) has been implicated inmammalian testicular and epididymal development. This study aimed toinvestigate ERK expression inthe immature and mature testes and epididymides ofbulls. Weevaluated ERK expression using immunoblot analysis and immunohistochemistry. Immunoblot analysis revealed that immature bull testes and epididymides had higher phosphorylated ERK (pERK) expression than mature bull testes and epididymides. pERK immunoreactivity was higher inimmature epididymides than inimmature testes. pERK was localised mostly inspermatogonia, undifferentiated sustentacular (Sertoli) cells, and interstitial (Leydig) cells inimmature testes, aswell asin some spermatocytes and spermatids inmature testes. Inimmature epididymides, the body and tail had higher pERK expression than the head, whereas pERK was broadly distributed throughout the stereocilia, basal cells, and connective tissues. pERK distribution inthe head ofmature epididymides was similar tothat inimmature epididymides, whereas few connective tissue cells were expressed inthe body and tail ofmature epididymides. Collectively, these results suggest that ERK isexpressed inthe testis and epididymis ofimmature and mature bulls with varying intensities, and therole ofERK inmale reproductive organs may include the specific function ofits development.