Induction of cardiac insulin-like growth factor I gene expression in pressure overload hypertrophy.
Molecular mechanisms regulating the cardiac hypertrophic response to increased hemodynamic load are understood poorly. Insulin-like growth factor I (IGF I) is a mitogen that is thought to play a key role in pre- and postnatal growth. To investigate a possible role of IGF I in the cardiac response to pressure overload, rats underwent banding of the ascending aorta immediately above the aortic valve using a hemoclip, or a sham procedure. An analysis of left-ventricular RNA by Northern hybridization using a 32P-labeled IGF I cDNA revealed four messenger ribonucleic acid transcripts of 7.6, 4.6, 1.7, and 0.9 to 1.2 Kb. Insulin-like growth factor I messenger ribonucleic acid was quantitated by ribonuclease protection assays using a rat exon 3 riboprobe. There was a sustained increase in IGF I mRNA levels that correlated temporally with the development of left ventricular hypertrophy. These results indicate that left ventricular pressure overload is associated with an induction of cardiac IGF I gene expression. Insulin-like growth factor I may play a role in the response to increases in wall stress and likely contribute to cardiac hypertrophy.
Hanson
M C
MC
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322.
Fath
K A
KA
Alexander
R W
RW
Delafontaine
P
P
D000818:Animals; D015152:Blotting, Northern; D003250:Constriction; D003326:Coronary Circulation / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D017379:Hypertrophy, Left Ventricular / Q000378:metabolism* / Q000503:physiopathology; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D011312:Pressure; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases