Open AccessRat liver and intestinal mucosa differ in the developmental pattern and hormonal regulation of carbamoyl‐phosphate synthetase I and ornithine carbamoyl transferase gene expression
Author(s) -
RYALL Jeremiah C.,
QUANTZ MacKenzie A.,
SHORE Gordon C.
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb09603.x
Subject(s) - biology , endocrinology , medicine , fetus , gene expression , ornithine transcarbamylase , messenger rna , ornithine carbamoyltransferase , ornithine , gene , pregnancy , biochemistry , urea cycle , arginine , amino acid , genetics
cDNA probes were empolyed to measure levels of carbamoyl‐phosphate synthethase I (CPS) and ornithine carbamoyltransferase (OCT) mRNAs in fetal and neonatal livers and intestines. In the fetal liver, significant levels of OCT mRNA were present at 15‐days gestation while CPS mRNA could not be detected until day 17 of fetal development. Apart from a small decline just after birth, amounts of both mRNAs increased steadily to reach adult levels in postnatal life. In contrast to the situation in liver, CPS and OCT mRNA levels in the fetal intestine rose rapidly to peak at day 21 of gestation and then declined steadily in the first seven days after birth. Using the methyl‐sensitive restriction isoschizomeric pair, Msp I/ Hpa II, the 5′ ends of both the CPS and OCT genes were shown to undergo demethylation during development. In the case of the OCT gene, however, the hypomethylation characteristic of the adult liver and intestinal mucosa was not observed in the 15‐day‐old fetal liver, where significant levels of gene expression had already been established. Levels of CPS and OCT mRNA in livers of adults responsed to glucagon in normal animals (1.5‐fold and 2.2‐fold increases, respectively) and to dexamethasone in experimentally induced diabetic animals (3‐fold increase in CPS mRNA with no change in OCT mRNA). These treatments were all without effect on the levels of CPS and OCT mRNA in intestinal mucosa.