Initiation and maintenance of spermatogenesis requires androgens, in particular testosterone, and FSH. Integral membrane proteins contribute essentially to the formation of the blood-testis barrier (BTB) and are therefore crucial for normal spermatogenesis. Recently, we investigated BTB protein and androgen receptor (AR) expression in whole testicular homogenates during GnRH- slow release implant mediated downregulation and subsequent restart of spermatogenesis following implant removal after 5 months (week 0). In the present study, RNA from tubular tissue only (500 round tubules/sample) of the respective animals castrated in week 0 (n = 3), 3 (n = 3), 6 (n = 4) and 12 (n = 3) was extracted and RT-qPCR was performed using primers against Ocld, Cldn-3, -11, Cx43 and AR. Tissue from 4 untreated dogs served as controls. Whereas no significant differences in mRNA expression of Cldn-3 and AR could be identified in tubular tissue between the downregulated testes, the different stages of restart of spermatogenesis and CG, relative gene expression for Cldn-11 (p = 0.0213), Cx43 (p = 0.0113) and Ocld (p = 0.0030) differed significantly between groups. The highest ratio for Cx43 and Cldn-11 was obtained in week 0. For Ocld, the relative mRNA expression was highest in weeks 6 and 12. The unchanged AR expression in tubular tissue at downregulation allows for a rapid responsiveness to androgens during restart of spermatogenesis. Whereas Cx43 and Cldn-11 seems to be upregulated during downregulation, results for Ocld indicate a rebound effect at the time when spermatogenesis is nearly re-established.