AJP - Endocrinology and Metabolism, Vol 254, Issue 5 E676-E679, Copyright © 1988 by American Physiological Society
Albumin gene transcription is enhanced in liver of nephrotic rats
A. Yamauchi, E. Imai, T. Noguchi, T. Tanaka, S. Yamamoto, H. Mikami, Y. Fukuhara, M. Fujii, Y. Orita and T. Kamada
First Department of Medicine, Osaka University Medical School, Japan.
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.
