(A) Schematic of experiments using Sparc floxed mouse (Con) and adipocyte specific Sparc KO mouse (Adip-KO). (B) Immunoblot analysis of SPARC protein in SAT, VAT, and hypothalamus (Hypo) in Con and Adip-KO mice. (C) Weight change in Con and Adip-KO female mice during 16 weeks of HFD (n = 12, 12, respectively). (D and E) GTT (D) and ITT (E) in Con and Adip-KO mice with 16 weeks of HFD (n = 7, 7, respectively). (F) Insulin (100 nM) response signaling at the indicated time in cultured primary adipocytes from Con and Adip-KO mice with or without SPARC (20 μg/mL) treatment for 24 hours. “N” indicates no treatment. (G and H) Immunoblot analysis and quantification of AKT phosphorylation (Ser 473) 5 minutes after insulin injection. The mice were pretreated with SPARC (100 μg) by i.p. injection 12 hours before the insulin injection and tissue collection. (I and J) Glycerol (I) and free fatty acid (FFA) (J) levels in ex vivo lipolysis assay with VAT from Con and Adip-KO mice after 24 hours of fasting (n = 4, 5, respectively). (K) Immunoblot analysis for lipolysis signaling in adipose tissue explants (SAT) from Con and Adip-KO mice after 24 hours of fasting (n = 4, 5, respectively). (L) Glycerol assay of SAT explants from Con and Adip-KO mice with or without ex vivo SPARC treatment (20 μg/mL) for 24 hours followed by stimulation with 10 μM norepinephrine (NE) (n = 4, 4, respectively). (M) Glycerol assay in differentiated adipocytes from adipose SVF of Con and Adip-KO mice with or without preincubation of SPARC (20 μg/mL) for 24 hours (n = 5, 4, respectively). The adipocytes were treated with NE (10 μM) for 4 hours to activate lipolysis and glycerol levels were measured in supernatants. Error bars represent the mean ± SEM. 2-tailed unpaired (C, H, I, and J), paired (L and M) t tests, and 2-way ANOVA test with Bonferroni’s multiple comparisons test for adjusted P values (D and E) were performed for statistical analysis. *P < 0.05; **P < 0.01.