Adjudin is known to specifically affect Sertoli-germ cell adhesion,resulting in germ cell loss from the seminiferous epitheliumand transient infertility. The apical ectoplasmic specialization(apical ES) was shown to be the primary target of adjudin sinceadhesion was unaffected in organs which lack this structure.Herein, we expand previous findings by treating rat pups withadjudin, and we aim to address two questions. First, can adjudinperturb germ cell adhesion in the seminiferous epithelium oftestes in which the apical ES is not yet present? Second, canadjudin affect assembly of the blood-testis barrier (BTB) at15-18 days of age? Interesting changes were noted whenaged-matched testes from control and adjudin-treated rats wereexamined, including a delay in the appearance of developinggerm cells, as well as a delay in the formation of the tubulelumen. Immunoblotting using antibodies against BTB-constituentproteins indicated that formation of the BTB was affected inrat pups gavaged with adjudin. These results were corroboratedby immunofluorescence microscopy which showed profound changesin the cellular distribution of tight junction (TJ) and basalES proteins. Moreover, the BTB was shown to be compromised in30-day old rats when its integrity was assessed by a functionalin vivo assay. By 45 days of age, however, the seminiferousepithelium of treated rats was indistinguishable from that ofcontrol rats. Collectively, these results demonstrate that adjudintargets the apical ES, as well as the basal ES and TJ, which
in turn delays assembly of the BTB.