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Contractile
Peritubular myoid cells are responsible for the contractile nature of the seminiferous tubule. This contraction helps move the spermatozoa and fluid to the rete testes. There are a number of mediators involved in the regulation of contraction. Oxytocin produced by leydig cells has been shown to be a driving factor in the contractions by acting on peritubular myoid cells. As no oxytocin receptors are found on the peritubular myoid cells it is thought the oxytocin causes the activation of the vasopressin receptors. However, the full mechanisms behind the contractibility are unknown. Other factors including transforming growth factor-β, prostaglandins and nitric oxide are also thought to be.