Blood-Testis Barrier, Junctional and Transport Proteins and Spermatogenesis
Brian P. Setchell
The term “blood-testis barrier” appears to have been first used by Chiquoine in an article on effects of cadmium on the testis, but evidence for such a barrier already existed, dating back to the early years of the twentieth century (see ref. 2 for early references). In a number of studies, it was shown that some dyes when injected into animals, stained most tissues, with the notable exceptions of the brain and the seminiferous tubules of the testis. The former observation was rapidly taken up and developed to form the basis for the concept of the blood-brain barrier, but it was only with the studies of Kormano that the true significance of the earlier observations on the testis was recognized. He showed that dyes which were excluded from the tubules of adult rats readily penetrated those of prepubertal animals. In addition, Kormano noticed that staining of interstitial cells with acriflavine also fell around the time of puberty, suggesting a change in the blood vessels as well. At about the same time as Kormano’s studies, Waites and I showed that testis blood flow measured by indicator dilution with rubidium gave much lower values that with iodoantipyrine, while similar values were obtained in most other organs except brain, suggesting that rubidium was also excluded to some extent from parts of the testis, as it was from the brain.