Apolipoprotein-E-gene expression in rat liver during development in relation to insulin and glucagon.
An apolipoprotein-E (apo-E) cDNA probe, cloned by immunoscreening of a lambda GT11 rat liver cDNA library, was used to further characterize the expression of the apo-E gene in rat liver during development, in relation to plasma insulin and glucagon levels. The apo-E mRNA level was low in fetus liver, then abruptly increased at birth and rose further during the suckling period. It returned to the level at birth in 10-week-old adults. These variations were paralleled with dramatic changes in plasma glucagon, which rose at birth and remained high during suckling. At the same time, the insulin/glucagon molar ratio fell. Administration of N6,O2-dibutyryl cAMP to 5-day-old rats resulted in a significant induction of liver apo-E mRNA. Moreover, liver apo-E mRNA rose in 10-h-fasted suckling rats as compared to controls, while plasma glucagon increased and the insulin/glucagon ratio decreased. Conversely, glucose feeding of suckling rats did not induce any increase in liver apo-E mRNA, the insulin/glucagon ratio was 10-fold higher than in fasted animals. Our results are consistent with liver apo-E gene expression being under the control of plasma glucagon and of the glucagon/insulin balance.
Mangeney
M
M
Unité associée 1283 du Centre National de la Recherche Scientifique, Faculté de Médecine Saint Antoine, Centre Hospitalier Universitaire, Paris, France.
Cardot
P
P
Lyonnet
S
S
Coupe
C
C
Benarous
R
R
Munnich
A
A
Girard
J
J
Chambaz
J
J
Bereziat
G
G
D000818:Animals; D000831:Animals, Newborn; D001057:Apolipoproteins E / Q000235:genetics*; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D005215:Fasting; D005796:Genes; D005934:Glucagon / Q000097:blood / Q000502:physiology*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000097:blood / Q000502:physiology*; D008099:Liver / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D001057:Apolipoproteins E; D007328:Insulin; D012333:RNA, Messenger; D004247:DNA; D005934:Glucagon; D005947:Glucose