Soluble soy protein peptic hydrolysate stimulates adipocyte differentiation in 3T3‐L1 cells

Scope The molecular mechanisms underlying the potential health benefit effects of soybean proteins on obesity‐associated metabolic disorders have not been fully clarified. In this study, we investigated the effects of soluble soybean protein peptic hydrolysate (SPH) on adipocyte differentiation by using 3T3‐L1 murine preadipocytes. Methods and results The addition of SPH increased lipid accumulation during adipocyte differentiation. SPH increased the mRNA expression levels of an adipogenic marker gene and decreased that of a preadipocyte marker gene, suggesting that SPH promotes adipocyte differentiation. SPH induced antidiabetic and antiatherogenic adiponectin mRNA expression and secretion. Moreover, SPH increased the mRNA expression levels of insulin‐responsive glucose transporter 4 and insulin‐stimulated glucose uptake. The expression levels of peroxisome proliferator‐activated receptor γ (PPARγ), a key regulator of adipocyte differentiation, during adipocyte differentiation were up‐regulated in 3T3‐L1 cells treated with SPH, and lipid accumulation during adipocyte differentiation induced by SPH was inhibited in the presence of a PPARγ antagonist. However, SPH did not exhibit PPARγ ligand activity. Conclusion These findings indicate that SPH stimulates adipocyte differentiation, at least in part, via the up‐regulation of PPARγ expression levels. These effects of SPH might be important for the health benefit effects of soybean proteins on obesity‐associated metabolic disorders.