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Induction of Cardiac Insulin-Like Growth Factor I Gene Expression in Pressure Overload Hypertrophy

1993; Elsevier BV; Volume: 306; Issue: 2 Linguagem: Inglês

10.1097/00000441-199308000-00001

1538-2990

Mark C. Hanson, Kenneth A. Fath, R. Wayne Alexander, Patrice Delafontaine,

Muscle Physiology and Disorders

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.