Yamauchi A, Imai E, Noguchi T, Tanaka T, Yamamoto S, Mikami H, Fukuhara Y, Fujii M, Orita Y, Kamada T
First Department of Medicine, Osaka University Medical School, Japan.
Am J Physiol. 1988 May;254(5 Pt 1):E676-9. doi: 10.1152/ajpendo.1988.254.5.E676.
The level of albumin mRNA and the transcription rate of the albumin gene were studied in the liver of control rats and rats with nephrosis induced by injection of the aminonucleoside of puromycin. Total RNA was extracted from liver by the guanidium thiocyanate method. The albumin mRNA level was measured by cDNA-RNA dot-blot hybridization, and the transcription rate of the albumin gene was measured by the "run-on" transcription assay using isolated nuclei. Urinary protein excretion in nephrotic rats was significantly higher than in control rats (258 +/- 132 vs. 12 +/- 2 mg/day), and the serum albumin concentration in nephrotic rats was significantly lower. There was no difference in body weight, liver weight, serum creatinine, or urea nitrogen between the two groups. Both the level of albumin mRNA and the transcription rate of the albumin gene in the nephrotic liver were about twice as high as those in the control liver. There was no difference in the level of beta-actin mRNA between the two groups. Northern blot analysis showed that both putative precursor RNA and the mature form of albumin mRNA were increased in nephrotic rats. We conclude that albumin synthesis is increased in the liver of nephrotic rats and a transcriptional process is responsible for this increase.
在对照大鼠以及通过注射嘌呤霉素氨基核苷诱导产生肾病的大鼠肝脏中，研究了白蛋白mRNA水平和白蛋白基因的转录速率。采用硫氰酸胍法从肝脏中提取总RNA。通过cDNA-RNA斑点杂交法测定白蛋白mRNA水平，使用分离的细胞核通过“连续”转录测定法测定白蛋白基因的转录速率。肾病大鼠的尿蛋白排泄量显著高于对照大鼠（258±132对12±2毫克/天），且肾病大鼠的血清白蛋白浓度显著降低。两组之间的体重、肝脏重量、血清肌酐或尿素氮没有差异。肾病肝脏中白蛋白mRNA水平和白蛋白基因的转录速率均约为对照肝脏中的两倍。两组之间β-肌动蛋白mRNA水平没有差异。Northern印迹分析表明，肾病大鼠中假定的前体RNA和成熟形式的白蛋白mRNA均增加。我们得出结论，肾病大鼠肝脏中白蛋白合成增加，且转录过程是这种增加的原因。
