Diet- and hormone-induced reversal of the carbamoylphosphate synthetase mRNA gradient in the rat liver lobulus.
A hybridocytochemical analysis of adult liver from normal control and from hormonally and dietary-treated rats was carried out, using radioactively-labelled probes for the mRNAs of glutamine synthetase (GS), carbamoylphosphate synthetase (CPS) and phosphoenolpyruvate carboxykinase (PEPCK). In line with previous findings, GS mRNA is exclusively expressed in a small pericentral compartment, CPS mRNA exclusively in a contiguous large periportal compartment and PEPCK mRNA across the entire porto-central distance. The density of labelling in CPS and PEPCK mRNA-positive hepatocytes decreases in a porto-central direction. Starvation resulted in a reversal of the gradient of CPS mRNA within its periportal compartment; glucose refeeding counteracted this effect. Livers of glucocorticosteroid-treated, starved or diabetic rats also revealed a reversal of the normal gradient of CPS mRNA, but now across the entire porto-central distance. The patterns of expression of GS and PEPCK mRNA remained essentially unchanged, notwithstanding substantial changes in the levels of expression. It is concluded that blood-borne factors constitute the major determinants for the expression patterns of CPS mRNA within the context of the architecture of the liver lobulus.
Moorman
A F
AF
Department of Anatomy and Embryology, University of Amsterdam, The Netherlands.
de Boer
P A
PA
Charles
R
R
Lamers
W H
WH
D000818:Animals; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / Q000235:genetics*; D015342:DNA Probes; D003907:Dexamethasone / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology*; D005974:Glutamate-Ammonia Ligase / Q000235:genetics*; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D009928:Organ Specificity; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000235:genetics*; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D015342:DNA Probes; D012333:RNA, Messenger; D003907:Dexamethasone; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D005974:Glutamate-Ammonia Ligase; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)