title: Insulin-induced translocation of facilitative glucose transporters in fetal/neonatal rat skeletal muscle.
abstract: We examined the effect of insulin on fetal/neonatal rat skeletal muscle GLUT-1 and GLUT-4 concentrations and subcellular distribution by employing immunohistochemical analysis and subcellular fractionation followed by Western blot analysis. We observed that insulin did not alter total GLUT-1 or GLUT-4 concentrations or the GLUT-1 subcellular distribution in fetal/neonatal or adult skeletal muscle in 60 min. The basal and insulin-induced changes in subcellular distribution of GLUT-4 were different between the fetal/neonatal and adult skeletal muscle. Under basal conditions, sarcolemma-associated GLUT-4 was higher in the newborn compared with the adult, translating into a higher glucose transport. In contrast, insulin-induced translocation of GLUT-4 to the sarcolemma- and insulin-induced glucose transport was lower in the newborn compared with the adult. This age-related change results in enhanced basal glucose transport to fuel myocytic proliferation and differentiation while relatively curbing the insulin-dependent glucose transport in the newborn.
authors.affiliation: University of Pittsburgh School of Medicine, Magee-Womens Research Institute, Pittsburgh, Pennsylvania 15213-3180, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: He
authors.forename: M
authors.initials: M
authors.lastname: Thamotharan
authors.forename: Sherin U
authors.initials: SU
authors.lastname: Devaskar
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001786:Blood Glucose / Q000032:analysis; D005333:Fetus / Q000187:drug effects / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001786:Blood Glucose; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495679:Slc2a1 protein, rat; C495694:Slc2a4 protein, rat