Open AccessNeonatal Intramuscular Injection of Plasmid DNA Encoding GLP-1 Reduces Serum Insulin Level and Modifies Skeletal Muscle Myosin Heavy Chain Composition in Adult Rats
Author(s) -
L Wang,
Furong Guo,
Shuhong Wei,
Ruqian Zhao
Publication year - 2010
Publication title -
physiological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.647
H-Index - 70
eISSN - 1802-9973
pISSN - 0862-8408
DOI - 10.33549/physiolres.931815
Subject(s) - medicine , endocrinology , glut4 , skeletal muscle , myosin , insulin , soleus muscle , biology , recombinant dna , transfection , messenger rna , chemistry , glucose transporter , gene , biochemistry
To test the hypothesis that neonatal GLP-1 exposure mayprogram myosin heavy chain (MyHC) composition in adultskeletal muscle, two-day-old rats were transfectedintramuscularly with vacant vector plasmid (VP), or recombinantplasmid expressing secretory GLP-1 at the doses of 60 μg (LG)and 120 μg (HG), respectively. Expression of GLP-1 mRNA wasdetected in muscles of both LG and HG rats 7 days aftertransfection, with more abundant GLP-1 transcript seen in LGrats. In accordance with the GLP-1 expression, LG ratsdemonstrated more significant responses to neonatal GLP-1exposure. Small yet significant growth retardation was observedin LG rats, which is accompanied with significantly reduced seruminsulin concentration at 8 weeks of age compared to VP rats. Theresponses of skeletal muscle were dependent on muscle type.Significant increase of PGC-1α and GLUT4 mRNA expression wasdetected in soleus of LG rats, whereas a MyHC type switch fromⅡB to Ⅰ was seen in gastrocnemius. These results indicate thatneonatal exposure of healthy pups to ectopic GLP-1 causesgrowth retardation with decreased serum insulin as well asmuscle type-dependent modifications in MyHC type compositionand metabolic gene expression in adult rats.