SCD4 deficiency affects lipolysis in the mouse heart. A: Adipose triglyceride lipase (ATGL) activity. Using a triglyceride analog that becomes fluorescent after hydrolysis, we measured ATGL activity as described in the Materials and Methods. B: ATGL, C: abhydrolase domain-containing protein 5 (ABHD5), D: protein kinase A (PKA), and E: G0/G1 switch gene 2 (G0S2) protein content and results of the densitometric analysis. The data are expressed as the mean ± SD. n = 10–12 mice/group. ap < 0.05, versus WT chow; bp < 0.05, versus WT HFD; cp < 0.05, versus SCD4−/− chow. ATGL, adipose triglyceride lipase; HFD, high-fat diet.