Species differences in contractility of seminiferous tubules and tunica albuginea as related to sperm transport through the testis.

Frequency and depth of contractions and tonus--i.e., diameter of the tubule or shift of the baseline for the capsule--of both the seminiferous tubules and the tunica albuginea were quantified for rat, mouse, rabbit, hamster and ground squirrel tests. In the ground squirrel, contractility was measured prior to, during and after breeding. The rat testes had the strongest tubular contractions; those of the mouse, squirrel and rabbit exhibited intermediate values, and the hamster tests had the weakest tubular contractions. The rabbit tests exhibited the strongest, most well-developed rhythmical capsular contractions while the rat, mouse, hamster and squirrel tests showed no definite rhythmical contractions. Hamster tests apparently depend primarily upon fluid secretion by the seminiferous tubules for sperm transport through the tests to the epididymis, while the squirrel, rat and mouse tests utilize both fluid secretion and some tubular contractions. The rat apparently utilizes tubular contractions more so than the other rodents studied for sperm transport.