Figure 7. Adiponectin promotes SOCS-3/OB-Rb association, in vitro.

A) Western Analysis for SOCS-3 after immunopreciptitation of Ob-Rb from rat HSCs treated for 1h with leptin (Lep, 100ng/ml), adiponectin (Adi, 10μg/ml), both (LA), or neither. No SOCS-3/Ob-Rb associated was detected in untreated or leptin-treated samples. Adiponectin stimulated SOCS-3/Ob-Rb association whether administered alone or in combination with leptin. B) Western Analysis for Ob-Rb[Tyr₁₁₃₈ and Tyr₉₈₅] after immunoprecipitation of SOCS-3 from rat HSCs treated for 1h with leptin, adiponetin, both or neither. In the presence of leptin, SOCS was associated with Ob-Rb phosphorylated at Tyr₉₈₅, but not at Tyr₁₁₃₈. In the presence of adiponectin, or adiponectin and leptin however, SOCS-3 was associated with Ob-Rb phosphorylated both Tyr₉₈₅ and Tyr₁₁₃₈. C) Western blot of pOb-Rb(Tyr₁₁₃₈), total Ob-Rb, and SOCS-3 from culture-activated rat HSCS treated for 1h with leptin (Lep, 100ng/ml), adiponectin (Adi, 10μg/ml), both (LA), or neither. Compared with untreated samples, adiponectin treatment suppressed Ob-Rb (Tyr₁₁₃₈) phosphorylation. Leptin stimulated Ob-Rb(Tyr₁₁₃₈) phosphorylation, but the stimulation was attenuated when leptin and adiponectin were administered together. Compared to untreated, SOCS-3 protein levels decreased in the presence of leptin, but increased in the presence of adiponectin. D) Quantitation of data presented in (7C) (*p < 0.05 vs. untreated; ^#p < 0.05 vs. leptin)