engleski

Immunolocalization of vacuolar proton-ATPase along the male reproductive tract in rat

The acid pH in the male reproductive tract conributes to the sperm maturation and motility. The cellular mechanisms of proton secretion in ducts along this tract are poorly characterized. Recently, it has been suggested that the "kidney" isoform of the vacuolar proton-ATPase (V-ATPase) may acidify the luminal fluid in the epididymis (E) and vas deferens (VD). The aim of this study was to locate the V-ATPase isoforms in various segments of the male reproductive tract in rat. Polyclonal antibodies against the 31 kDa (common isoform) and 56 kDa ("kidney" isoform) V-ATPase subunits were raised in rabbits and used in immunoblotting studies with the total plasma membranes (PM) from various segments of the male rat reproductive tract, and in immunocytochemical studies in 4 m thick cryosections of the in vivo fixed testis (T), rete testis (RT), efferent duct (ED), E, VD, seminal vesicles (SV), and the prostate (P). By immunoblotting, both V-ATPase subunits were demonstrated in various concentrations in PM from all the reproductive tract segments. By immunocytochemistry, the 31 kDa subunit was localized to the Golgi membranes in the T, SV, and P cells, and to the lumenal cell membranes in the special cells of RT, ED (nonciliated cells), E and VD (clear cells), and P (occassional clear cells). The anti-56 kDa V-ATPase subunit ("kidney" isoform) antibody weakly labeled the Golgi membranes in the T, SV, and P, and intensely labeled the apical membrane domain in the clear cells of E, VD, and P. The cells in RT and DE were not labeled with this antibody. Conclusion: a) the V-ATPase-positive cells that may contribute to the proton secretion reside in most segments of the male reproductive tract, b) the cells in RT and ED contain the "brain" isoform of the V-ATPase, whereas the "kidney" isoform of this ATPase is present in cells from other segments.

immunolocalization; vacuolar H+-ATPase; male reproductive

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