title: Silk protein hydrolysate increases glucose uptake through up-regulation of GLUT 4 and reduces the expression of leptin in 3T3-L1 fibroblast.
abstract: The purpose of our research was to test the hypothesis that silk protein hydrolysate increases glucose uptake in cultured murine embryonic fibroblasts. Insulin sensitizing activity was observed in a cell-based glucose uptake assay using 3T3-L1 embryonic fibroblasts. The treatment of 1 mg/mL of silk peptide E5K6 plus 0.2 nM insulin was associated with a significant increase in glucose uptake (124.0% ± 2.5%) compared to treatment with 0.2 nM insulin alone. When the 3T3-L1 cells were induced to differentiate into fibroblasts, fat droplets formed inside the cells. Silk peptide E5K6 reduced the formation of fat droplets at the 1-mg/mL dosage (86.1% ± 2.5%) when compared to the control (100.0% ± 5.8%). A 1 mg/mL dose of silk peptide E5K6 significantly increased GLUT 4 expression (131.5% ± 4.0%). The treatment of 1 mg/mL of silk peptide E5K6 did not present any changes for adipogenic expressed genes, but leptin expression was significantly increased by silk peptide E5K6 supplementation (175.9% ± 11.1%). From these results, silk peptide E5K6 increased glucose uptake via up-regulation of GLUT 4 and decreased fat accumulation via the up-regulation of leptin.
authors.affiliation: Institute of Health Science, Korea University, Seoul 136-703, Korea.
authors.forename: Hyun-Sun
authors.initials: HS
authors.lastname: Lee
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Lee
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Suh
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D012831:Bombyx; D002454:Cell Differentiation / Q000187:drug effects; D005223:Fats / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D007333:Insulin Resistance / Q000235:genetics; D020738:Leptin / Q000378:metabolism*; D050356:Lipid Metabolism / Q000187:drug effects; D051379:Mice; D010455:Peptides / Q000494:pharmacology*; D011492:Protein Hydrolysates / Q000494:pharmacology*; D047011:Silk / Q000494:pharmacology*; D015854:Up-Regulation
chemical_list: D005223:Fats; D051275:Glucose Transporter Type 4; D020738:Leptin; D010455:Peptides; D011492:Protein Hydrolysates; D047011:Silk; D005947:Glucose