Insulin growth factor-1 receptor (IGF-1R)/Akt signaling pathway in human primary subcutaneous preadipocytes (HPAs) and differentiated HPAs after intermittent normoxia (IN) or intermittent hypoxia (IH) exposure. The protein expressions of IGF-1Rβ and phosphorylated protein p-Akt (Ser 473) in HPAs (a–c) and in differentiated HPAs (d–f) were examined by Western blots. . Bars: mean ± SEM. .