In vitro effects of estradiol-17β on myoid and fibroblastic cell proliferation in the immature rainbow trout testis

This study sought to determine whether estradiol-17β (E₂) could induce proliferation of interstitial cells (fibroblasts and myoid cells) in the immature rainbow trout (Oncorhynchus mykiss) testis. To investigate this, a floating organ culture system was utilized. The results showed that a dose of 18.3n M E₂ added to the medium significantly increased interstitial cell proliferation. Pretreatment of the tissue with the estrogen receptor antagonist ICI 182,780 nullifies this proliferative effect. These results show that E₂ can enhance interstitial cell proliferation in the immature rainbow trout testis before spermatogenesis begins.