Elevated blood pressure and enhanced myocardial contractility in mice with severe IGF-1 deficiency.
To circumvent the embryonic lethality of a complete deficiency in insulin-like growth factor 1 (IGF-1), we generated mice homozygous for a site-specific insertional event that created a mutant IGF-1 allele (igf1m). These mice have IGF-1 levels 30% of wild type yet survive to adulthood, thereby allowing physiological analysis of the phenotype. Miniaturized catheterization technology revealed elevated conscious blood pressure in IGF-1(m/m) mice, and measurements of left ventricular contractility were increased. Adenylyl cyclase activity was enhanced in IGF-1(m/m) hearts, without an increase in beta-adrenergic receptor density, suggesting that crosstalk between IGF-1 and beta-adrenergic signaling pathways may mediate the increased contractility. The hypertrophic response of the left ventricular myocardium in response to aortic constriction, however, was preserved in IGF-1(m/m) mice. We conclude that chronic alterations in IGF-1 levels can selectively modulate blood pressure and left ventricular function, while not affecting adaptive myocardial hypertrophy in vivo.
Duke Scholars
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Related Subject Headings
- Sex Characteristics
- Receptors, Adrenergic, beta
- Polymerase Chain Reaction
- Pituitary Gland
- Myocardial Contraction
- Mutagenesis, Site-Directed
- Mutagenesis, Insertional
- Mice, Mutant Strains
- Mice
- Male
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Sex Characteristics
- Receptors, Adrenergic, beta
- Polymerase Chain Reaction
- Pituitary Gland
- Myocardial Contraction
- Mutagenesis, Site-Directed
- Mutagenesis, Insertional
- Mice, Mutant Strains
- Mice
- Male