Premium
Hepatic glutaminase mRNA is confined to part of the urea cycle domain in the adult rodent liver lobule
Author(s) -
Moorman Antoon F.M.,
de Boer Pict A.J.,
Watford Malcolm,
Dingemanse Maria A.,
Lamers Wouter H.
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01230-x
Subject(s) - urea cycle , rodent , glutaminase , lobules of liver , rodent model , urea , chemistry , messenger rna , microbiology and biotechnology , biochemistry , biology , medicine , endocrinology , glutamine , ecology , gene , amino acid , arginine
This in situ hybridization study describes the developmental appearance of the lobular distribution of the mRNA encoding hepatic glutaminase in normal rat liver. Glutaminase has been proposed to provide the urea cycle with ammonia [Hässinger and Gerok (1983) Eur. J. Biochem. 133, 269–275]. Hence, the (developmental) pattern of expression of the mRNA would be expected to be closely linked to that of the urea cycle enzymes. From embryonic day 20 onward, hepatic glutaminase mRNA can be detected along the entire porto‐central axis, with predominant expression in the portal area. In the adult phenotype, which is acquired at the end of the first postnatal week, glutaminase mRNA is no longer present along the entire porto‐central distance but has become confined to a relatively small periportal domain in which the expression decreases in a porto‐central direction. Thus, in contrast to the large periportal domain, in which the urea cycle enzymes are expressed, the glutaminase mRNA‐expressing domain is much smaller and not contiguous with the glutamine synthase mRNA‐expressing pericentral domain, leaving a midlobular area that is devoid of glutaminase mRNA. A similar pattern of distribution was found in adult mouse liver. The significance of these observations is that, within the liver lobules, there is an area in which glutaminase is not expressed and, hence, glutamine can not be the substrate for urea synthesis.