Expression and regulation of insulin-like growth factor-binding protein-1, -2, -3, and -4 messenger ribonucleic acids in purified rat Leydig cells and their biological effects.
Expression and regulation of insulin-like growth factor-binding protein-1, -2, -3, and -4 messenger ribonucleic acids in purified rat Leydig cells and their biological effects.
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DOI：
10.1210/endo.132.5.7682935
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发表时间：
1993-05
期刊：
影响因子：
4.8
通讯作者：
T. Lin;Deli Wang;M. Nagpal;S. Shimasaki;N. Ling
中科院分区：
文献类型：
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作者：
T. Lin;Deli Wang;M. Nagpal;S. Shimasaki;N. Ling
胰岛素样生长因子- i （IGF-I）的作用受到结合蛋白[IGF-binding proteins， igfbp]的修饰。之前，我们报道了IGF-I促进间质细胞的类固醇生成，并且IGF-I mRNA在间质细胞中表达。在本研究中，我们评估了IGFBP-1、-2、-3和-4在纯化大鼠间质细胞中的表达和调控及其生物学效应。我们发现睾丸粗间质细胞、纯化间质细胞或精小管均不表达IGFBP-1 mRNA。这表明IGFBP-1 mRNA在睾丸中未以可检测的量表达。相比之下，纯化的间质细胞中大量表达1.8千碱基（kb）的IGFBP-2，而粗间质细胞中表达量较少。IGFBP-2 mRNA在精管中有少量表达，在肝脏中无表达。igfbp - 3mrna主要在纯化的间质细胞、粗间质细胞和肝脏中表达，而在精小管中未发现相当数量的表达。肝脏IGFBP-4 mRNA表达量最高，纯化间质细胞和粗间质细胞IGFBP-4 mRNA表达量较低。接下来，我们评估了间质细胞中IGFBP mrna对垂体的依赖性。从50日龄大鼠垂体切除5天后分离纯化的间质细胞。垂体切除术后，间质细胞中IGFBP-2、-3和-4 mRNA水平分别下降22%、80%和90%以上。然而，在肝脏中，IGFBP-2 mRNA水平升高，IGFBP-3 mRNA水平降低，而IGFBP-4保持不变。正如预期的那样，垂体切除术导致间质细胞中大量（7.0- 7.5 kb，减少75%）和少量（0.8- 1.2 kb，减少90%）IGF-I mRNA水平下降。垂体切除术也降低肝脏中IGF-I mRNA的表达。最后，研究了IGFBP-2、-3和-4对间质细胞睾酮形成的影响。浓度为10 ng/ml的hCG使睾酮的形成从0.6 +/- 0.01增加到27.4 +/- 1.01 ng/10(6)个细胞。h。在igf - 1 （10 ng/ml）存在的情况下，睾酮的形成进一步增加，达到58.6 +/- 1.6 ng/10(6)个细胞。h （P < 0.01）。IGFBP-3（0.1、1和2.5 pmol/ml）对igf - 1 + hcg诱导的睾酮形成产生剂量依赖性抑制。浓度为2.5 pmol/ml的IGFBP-3完全中和了igf - 1对间质细胞类固醇生成的影响。IGFBP-4的作用较小，而IGFBP-2对IGF-I + hcg诱导的睾酮形成没有影响。（摘要删节为400字）
The actions of insulin-like growth factor-I (IGF-I) are modified by binding proteins [IGF-binding proteins (IGFBPs)]. Previously, we reported that IGF-I enhances Leydig cell steroidogenesis and that IGF-I mRNA is expressed in Leydig cells. In the present study, we evaluated the expression and regulation of IGFBP-1, -2, -3, and -4 in purified rat Leydig cells and their biological effects. We found that none of the testicular crude interstitial cells, purified Leydig cells, or seminiferous tubules expressed IGFBP-1 mRNA. This indicated that IGFBP-1 mRNA is not expressed in the testis in detectable amounts. In contrast, large amounts of IGFBP-2 with a size of 1.8 kilobases (kb) were expressed in purified Leydig cells, and lesser amounts in crude interstitial cells. Small amounts of IGFBP-2 mRNA were expressed in seminiferous tubules, but none could be detected in liver. IGFBP-3 mRNA was predominantly expressed in purified Leydig cells, crude interstitial cells, and liver, while appreciable amounts were not found in seminiferous tubules. Liver had the highest amounts of IGFBP-4 mRNA, whereas purified Leydig cells and crude interstitial cells had lesser amounts. We next evaluated the pituitary dependency of IGFBP mRNAs in Leydig cells. Purified Leydig cells were isolated from 50-day-old rats 5 days after hypophysectomy. IGFBP-2, -3, and -4 mRNA levels in Leydig cells decreased 22%, 80%, and more than 90%, respectively, after hypophysectomy. In the liver, however, IGFBP-2 mRNA levels increased, and IGFBP-3 mRNA levels decreased, while IGFBP-4 remained unchanged. As expected, hypophysectomy caused decrements in large (7.0- to 7.5-kb; a 75% reduction) and small (0.8- to 1.2-kb; a 90% reduction) IGF-I mRNA levels in Leydig cells. Hypophysectomy also reduced IGF-I mRNA expression in liver. Finally, the effects of IGFBP-2, -3, and -4 on Leydig cell testosterone formation were investigated. hCG in a concentration of 10 ng/ml increased testosterone formation from 0.6 +/- 0.01 to 27.4 +/- 1.01 ng/10(6) cells.h. In the presence of IGF-I (10 ng/ml), testosterone formation was further increased to 58.6 +/- 1.6 ng/10(6) cells.h (P < 0.01). IGFBP-3 (0.1, 1, and 2.5 pmol/ml) caused a dose-dependent inhibition of IGF-I- plus hCG-induced testosterone formation. IGFBP-3 in a concentration of 2.5 pmol/ml completely neutralized the effects of IGF-I on Leydig cell steroidogenesis. IGFBP-4 had a lesser effect, while IGFBP-2 had no effect on IGF-I- plus hCG-induced testosterone formation.(ABSTRACT TRUNCATED AT 400 WORDS)