Coordinated expression of UT-A and UT-B urea transporters in rat testis

R. A. Fenton, G. J. Cooper, I. D. Morris, C. P. Smith

    Research output: Contribution to journalArticlepeer-review


    The blood-seminiferous tubule barrier is responsible for maintaining the unique microenvironment conducive to spermatogenesis. A key feature of the blood-testis barrier is selective permeability to solutes and water transport, conferred by the Sertoli cells of the seminiferous tubules (SMTs). Movement of fluid into the lumen of the seminiferous tubule is crucial to spermatogenesis. By Northern analysis, we have shown that 4.0-, 3.3-, 2.8-, and ∼1.7-kb UT-A mRNA transcripts and a 3.8-kb UT-B mRNA transcript are detected within rat testis. Western analysis revealed the expression of both characterized and novel UT-A and UT-B proteins within the testis. Immunolocalization studies determined that UT-A and UT-B protein expression are coordinated with the developmental stage of the SMT. UT-A proteins were detected in Sertoli cell nuclei at all stages of tubule development and in residual bodies of stage VIII tubules. UT-B protein was expressed on Sertoli cell membranes of stage II-III tubules. Using in vitro perfusion, we determined that a phloretin-inhibitable urea pathway exists across the SMTs of rat testis and conclude that UT-B is likely to participate in this pathway.
    Original languageEnglish
    Pages (from-to)C1492-C1501
    JournalAmerican Journal of Physiology: Cell Physiology
    Issue number6
    Publication statusPublished - 2002


    • Residual bodies
    • Sertoli cell
    • Spermatogenesis
    • Urea flux


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