Dual estrogenic regulation of the nuclear progestin receptor and spermatogonial renewal during gilthead seabream (Sparus aurata) spermatogenesis.
Studies in teleosts suggest that progestins have crucial functions during early spermatogenesis. However, the role of the different progestin receptors in these mechanisms is poorly understood. In this work, we investigated the expression pattern and hormonal regulation of the classical nuclear progestin receptor (Pgr) in the gilthead seabream at three different stages of spermatogenesis: the resting (postspawning) phase, onset of spermatogenesis, and spermiation. Immunolocalization experiments using a seabream specific Pgr antibody revealed that the receptor was expressed in Sertoli and Leydig cells, and also in a subset of spermatogonia type A, throughout spermatogenesis. Short-term treatment of testis explants with 17β-estradiol (E2) increased pgr mRNA expression at all stages, while the progestin 17α,20β-dihydroxy-4-pregnen-3-one (17,20βP) had the opposite effect. At the resting stage, Sertoli cell Pgr expression was positively correlated with the occurrence of proliferating spermatogonia type A in the tubules, and both processes were incremented in vitro by E2 likely through the estrogen receptor alpha (Era) expressed in Sertoli and Leydig cells. In contrast, treatment with 17,20βP downregulated Pgr expression in somatic cells. The androgen 11-ketotestosterone (11-KT) upregulated pgr expression in Leydig cells and promoted the proliferation of mostly spermatogonia type B, but only during spermiation. No relationship between the changes in the cell type-specific expression of the Pgr with the entry into meiosis of germ cells was found. These data suggest a differential steroid regulation of Pgr expression during seabream spermatogenesis and the potential interplay of the E2/Era and 17,20βP/Pgr pathways for the maintenance of spermatogonial renewal rather than entry into meiosis.
['Chauvigné|François|F|', 'Parhi|Janmejay|J|', 'Ollé|Judith|J|', 'Cerdà|Joan|J|']
D021581:Active Transport, Cell Nucleus D000818:Animals D017756:Aquaculture D002467:Cell Nucleus D000066673:Cell Self Renewal D015536:Down-Regulation D004958:Estradiol D047628:Estrogen Receptor alpha D029941:Fish Proteins D018507:Gene Expression Regulation, Developmental D006908:Hydroxyprogesterones D007985:Leydig Cells D008297:Male D011980:Receptors, Progesterone D021541:Sea Bream D012708:Sertoli Cells D013091:Spermatogenesis D013093:Spermatogonia D013739:Testosterone D046509:Tissue Culture Techniques D015854:Up-Regulation
Spermatogenesis Estradiol Nuclear progesterone receptor Spermatogonia proliferation