College of Biological Science and Technology, Beijing Forestry University, Beijing 100083, China.
College of Biological Science and Technology, Beijing Forestry University, Beijing 100083, China.
J Steroid Biochem Mol Biol. 2019 Nov;194:105433. doi: 10.1016/j.jsbmb.2019.105433. Epub 2019 Jul 31.
The steroid hormones not only exert various endocrine functions but also act as the autocrine or paracrine factors in different tissues of mammals. In the present study, the seasonal expressions of androgen receptor (AR), estrogen receptors alpha and beta (ERα and ERβ), aromatase cytochrome P450 (P450arom) and 5α-reductase 1, 2 were investigated in the epididymis of the muskrat. HE staining showed enlarged lumen and abundant sperm in the breeding season while reduced lumen with no sperm in the non-breeding season. The staining of AR was presented in nuclei of epithelial cells of the epididymis in both seasons. The immunostaining of ERα was localized in both nuclei and cytoplasm of epithelial cells of the epididymis during the breeding season, while the weak staining of ERα was only in the nuclei of epithelial cells during the non-breeding season. In contrast, ERβ signal was negative in the epididymis of the muskrat in both seasons. The positive signals for P450arom and 5α-reductase 1, 2 were found in the cytoplasm of epithelial and smooth muscle cells during both seasons. Moreover, the protein and mRNA expression levels of AR, ERα, P450arom and 5α-reductase 1, 2 were significantly higher in the epididymis during the breeding season than those of the non-breeding season, and the expression level of 5α-reductase 1 was higher when compared with 5α-reductase 2. In addition, the levels of testosterone (T) and dihydrotestosterone (DHT) in the epididymis and serum were remarkably higher during the breeding season. Taken together, these findings suggested androgen and estrogen might play an important endocrine or autocrine/paracrine role to regulate the epididymal functions of the muskrat.
甾体激素不仅发挥各种内分泌功能，而且还作为自分泌或旁分泌因子在哺乳动物的不同组织中发挥作用。本研究探讨了雄甾酮受体（AR）、雌激素受体α和β（ERα和 ERβ）、细胞色素 P450 芳香化酶（P450arom）和 5α-还原酶 1、2 在麝鼠附睾中的季节性表达。HE 染色显示在繁殖季节，管腔扩大，精子丰富，而非繁殖季节管腔缩小，无精子。AR 的染色呈现在附睾上皮细胞的细胞核中，两个季节均有。ERα 的免疫染色在繁殖季节定位于附睾上皮细胞的细胞核和细胞质中，而非繁殖季节仅在细胞核中呈现弱染色。相比之下，ERβ 在两个季节的麝鼠附睾中均呈阴性信号。P450arom 和 5α-还原酶 1、2 的阳性信号在两个季节的上皮细胞和平滑肌细胞的细胞质中均有发现。此外，AR、ERα、P450arom 和 5α-还原酶 1、2 的蛋白和 mRNA 表达水平在繁殖季节的附睾中显著高于非繁殖季节，5α-还原酶 1 的表达水平高于 5α-还原酶 2。此外，繁殖季节附睾和血清中的睾酮（T）和二氢睾酮（DHT）水平显著升高。综上所述，这些发现表明雄激素和雌激素可能发挥重要的内分泌或自分泌/旁分泌作用，以调节麝鼠附睾的功能。
