Dipartimento di Biologia, Università degli studi di Napoli Federico II, Naples, Italy.
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli studi della Campania "Luigi Vanvitelli", Caserta, Italy.
J Exp Zool B Mol Dev Evol. 2019 Sep;332(6):198-209. doi: 10.1002/jez.b.22896. Epub 2019 Aug 21.
The quail Coturnix coturnix is a seasonal breeder with a physiological switch on/off of gonadic activity. Photoperiod and temperature are the major environmental factors regulating the spermatogenesis. To more thoroughly comprehend the steroidogenic pathways that govern the seasonal reproductive cycle, we have investigated the localization of StAR protein and steroidogenic enzymes (3β-HSD, 17β-HSD, P450 aromatase, and 5α-Red) as well as androgen and estrogen levels, in the testis of reproductive and nonreproductive quails. We demonstrated that StAR, 3β-HSD, 17β-HSD, P450 aromatase, and 5α-Red were always present in the somatic (Leydig and Sertoli cells) and germ cells (spermatogonia, spermatocytes I and II, spermatids, and spermatozoa). In addition, by western blot analysis, we demonstrated that 17β-HSD, P450 aromatase, and 5α-Red showed the highest expression levels during the reproductive testis compared with nonreproductive one. Accordingly, we also found that during the reproductive phase the highest titres of testosterone, 17β-estradiol, and 5α-dihydrotestosterone are recorded. In conclusion, our findings demonstrated that in C. coturnix: (a) both somatic and germ cells are involved in the local synthesis of sex hormones; (b) 17β-HSD, P450 aromatase, and 5α-Red expressions, as well as testicular androgens and estrogens, increased in reproductive quail testis. This study strongly indicates that the steroidogenic process in quail testis exhibits seasonal changes with the promotion of both androgenic and estrogenic pathways in the reproductive period, suggesting their synergic mechanism in the spermatogenesis regulation.
鹌鹑 Coturnix coturnix 是一种季节性繁殖者，其性腺活动具有生理开关。光周期和温度是调节精子发生的主要环境因素。为了更深入地了解控制季节性生殖周期的类固醇生成途径，我们研究了 StAR 蛋白和类固醇生成酶（3β-HSD、17β-HSD、P450 芳香酶和 5α-还原酶）以及雄激素和雌激素水平在生殖和非生殖鹌鹑睾丸中的定位。我们证明，StAR、3β-HSD、17β-HSD、P450 芳香酶和 5α-还原酶始终存在于体细胞（Leydig 和 Sertoli 细胞）和生殖细胞（精原细胞、初级精母细胞 I 和 II、精细胞和精子）中。此外，通过 Western blot 分析，我们证明与非生殖睾丸相比，17β-HSD、P450 芳香酶和 5α-还原酶在生殖睾丸中表达水平最高。相应地，我们还发现，在生殖阶段，睾丸酮、17β-雌二醇和 5α-二氢睾丸酮的浓度最高。总之，我们的研究结果表明，在 C. coturnix 中：（a）体细胞和生殖细胞都参与了性激素的局部合成；（b）17β-HSD、P450 芳香酶和 5α-还原酶的表达以及睾丸雄激素和雌激素在生殖鹌鹑睾丸中增加。这项研究强烈表明，鹌鹑睾丸的类固醇生成过程具有季节性变化，在生殖期促进了雄激素和雌激素途径，表明它们在精子发生调节中具有协同机制。
