Stabile Veronica, Russo Maria, Chieffi Paolo
Dipartimento di Medicina Sperimentale, II Università di Napoli, Via Costantinopoli, 16, 80138 Napoli, Naples, Italy.
Reproduction. 2006 Sep;132(3):477-84. doi: 10.1530/rep.1.01107.
Several lines of evidence support the key role of estrogens in male fertility. Here, we investigate the regulation of the serine/threonine kinase Akt-1 in the frog (Rana esculenta) testis during the annual sexual cycle and, whether 17beta-estradiol (E2) exerts a role in the Akt-1 activity. Akt-1 has been shown to be the mediator of growth factor-dependent cell proliferation, survival, and metabolism in a variety of cell types. First, we demonstrate by immunohistochemistry, the presence of estrogen receptor-beta (ERbeta), and Akt-1 in the spermatogonia (SPG), spermatocytes (SPC), and spermatids (SPT). Western-blot analysis revealed that ERbeta isoform (molecular weight 55 kDa) was highly expressed in May (reproductive period) with respect to January and November (winter stasis); in parallel, Akt-1 (molecular weight 60 kDa) is highly phosphorylated (Ser-473) during the period of active spermatogenesis (May) compared with the winter stasis (January and November). In addition, in vitro experiments demonstrate that E2 treatment induces the activation of Akt-1, and this effect is counteracted by the anti-estrogen ICI 182-780. In conclusion, our data show that E2 induces Akt-1 phosphorylation (Ser-473) possibly via ERbeta in frog (R. esculenta) male germ cells.
多条证据支持雌激素在男性生育中的关键作用。在此，我们研究了在青蛙（食用蛙）睾丸年度性周期中丝氨酸/苏氨酸激酶Akt-1的调节情况，以及17β-雌二醇（E2）是否在Akt-1活性中发挥作用。Akt-1已被证明是多种细胞类型中生长因子依赖性细胞增殖、存活和代谢的介质。首先，我们通过免疫组织化学证明了精原细胞（SPG）、精母细胞（SPC）和精子细胞（SPT）中存在雌激素受体β（ERβ）和Akt-1。蛋白质印迹分析显示，与1月和11月（冬季静止期）相比，ERβ异构体（分子量55 kDa）在5月（生殖期）高表达；同时，与冬季静止期（1月和11月）相比，Akt-1（分子量60 kDa）在活跃精子发生期（5月）高度磷酸化（Ser-473）。此外，体外实验表明，E2处理可诱导Akt-1激活，且这种作用被抗雌激素ICI 182-780抵消。总之，我们的数据表明，E2可能通过ERβ诱导青蛙（食用蛙）雄性生殖细胞中Akt-1磷酸化（Ser-473）。
