Figure 5.

Regulation of Cldn1 in the initial segment (A–C) of the adult rat epididymis. In intact adult rats (A), Cldn1 is immunolocalized to the lateral plasma membranes between neighboring principal cells (arrows) and between principal and basal cells (arrowheads). In adult rats, 14 days after orchidectomy (B), immunoreactive Cldn1 is associated at the interface between basal and principal cells (arrowheads) and not between the lateral plasma membranes of adjacent principal cells. In orchidectomized rats given testosterone replacement (C), immunoreactive Cldn1 is observed between the lateral plasma membranes at apical sites in areas of tight junctions (arrows), but not at more distal sites of these membranes; reaction, however, is maintained between basal and principal cells (arrowheads). P, Principal cells; B, basal cells; IT, intertubular space; L, lumen. Magnification, ×640. Reproduced from Gregory et al.,¹³⁷.