Expression of cellular retinol-binding protein and lecithin-retinol acyltransferase in developing rat testis.
Expression of cellular retinol-binding protein and lecithin-retinol acyltransferase in developing rat testis.
复制标题
细胞视黄醇结合蛋白和卵磷脂视黄醇酰基转移酶在发育中的大鼠睾丸中的表达。
DOI：
10.1095/biolreprod49.5.972
复制
发表时间：
1993
影响因子：
3.6
通讯作者：
Ong,DE
中科院分区：
文献类型：
--
作者：
Schmitt,MC;Ong,DE
哺乳动物中维生素A缺乏导致血-睾丸屏障近腔侧生殖细胞的损失，表明需要由周围的支持细胞提供的维生素A。细胞视黄醇结合蛋白（CRBP）和卵磷脂-视黄醇酰基转移酶（LRAT）是在支持细胞中发现的两种蛋白质，已知它们参与维生素A的运输。为了澄清这两种蛋白质的作用，在维生素A的交付到发展中的生殖细胞，我们已经研究了它们的细胞特异性表达的变化在青春期的开始在大鼠。在成年大鼠中，支持细胞CRBP的表达随生精上皮的周期而变化。在这里，我们表明，CRBP免疫反应性的强度的差异是可检测的支持细胞的不同小管早在出生后第4天，减数分裂开始之前。这表明CRBP的支持细胞的可变表达是独立于晚期生殖细胞建立的，并且可以预测在adult.We中看到的周期性变化，进一步证明了LRAT在大鼠睾丸中的比活性在出生后第20天和第35天之间增加了10倍。这种增加可归因于减数分裂后生殖细胞的出现：从青春期后大鼠睾丸的圆形精细胞富集细胞组分制备的微粒体的LRAT活性可以解释在整个睾丸中观察到的大部分LRAT活性。近腔生殖细胞内存在LRAT活性表明它们以视黄醇的形式接受维生素A，并合成已显示存在于成熟精子中的视黄酯。
Vitamin A deficiency in mammals results in the loss of germ cells on the adluminal side of the blood-testis barrier, suggesting a need for vitamin A that would be supplied by the surrounding Sertoli cells. Cellular retinol-binding protein (CRBP) and lecithin-retinol acyltransferase (LRAT) are two proteins found in Sertoli cells that are known to be involved in vitamin A trafficking. To clarify the role of these two proteins in the delivery of vitamin A to developing germ cells, we have examined changes in their cell-specific expression during the onset of puberty in the rat.In adult rats, Sertoli cell expression of CRBP varies with the cycle of the seminiferous epithelium. Here, we demonstrate that differences in the intensity of CRBP immunoreactivity are detectable in Sertoli cells of different tubules as early as postnatal Day 4, prior to the onset of meiosis. This indicates that variable expression of CRBP by Sertoli cells is established independently of late germ cells and may anticipate the cyclical variation seen in the adult.We further demonstrate that the specific activity of LRAT in rat testis increases tenfold between postnatal Days 20 and 35. This increase is attributable to the appearance of post-meiotic germ cells: the LRAT activity of microsomes prepared from a round spermatid-enriched cell fraction from post-pubertal rat testis could account for the majority of the LRAT activity observed in the whole testis. The presence of LRAT activity within adluminal germ cells suggests that they receive vitamin A as retinol and synthesize the retinyl esters that have been shown to be present in mature sperm.