ATGLi inhibits isoproterenol-induced lipolytic activity in adipose tissue without affecting cardiac lipolysis. (A, B) Effects of ISO and ATGLi on FA and glycerol release from murine gonadal adipose tissue explants (n = 6). Adipose tissue expands were preincubated with ± ATGLi (40 µM) for 8 h and subsequently stimulated with ± ATGLi (40 µM) ± ISO (100 µM) for 2 h. NEFA and glycerol release are shown. NEFA and glycerol release of each condition was averaged per animal and used as an experimental unit. (Small graph) White adipose tissue (WAT) FA release in CTRL/ISO- and ATGLi/ISO-treated mice (n = 6 per group) 12 days after final ISO injection. Gonadal adipose tissue explants were incubated with ± Forskolin (10 µM) for 1 h. Shown is the ratio of Forskolin-induced to basal NEFA release. (C–E) RT-qPCR analysis of lipolytic enzymes in adipose tissue 12 days after last ISO injection. n = 7 per group. (C) ATGL; (D) Hormone-sensitive lipase (HSL); (E) Monoglyceride lipase (MGL). (F) Immunoblots and densitometric quantification of (G) ATGL, (H) HSL, and (I) MGL in adipose tissue 12 days after last ISO injection. n = 3 per group. (J) RT-qPCR analysis of cardiac ATGL expression 2 days after last ISO injection. n = 7 per group. (K–M) Immunoblots of ATGL, HSL, P-HSL (Ser 563), and P-HSL (Ser 660) as well as densitometric quantification of (L) ATGL and (M) HSL in cardiac tissue 2 days after last ISO injection. n = 3 per group. (N) Basal and CGI-58 stimulated TAG hydrolase activity in cardiac tissue of CTRL/ISO- and ATGLi/ISO-treated mice. (O) Cardiac TAG levels 12 days after last ISO injection, assessed by LC/MS. Age-matched C57BL/6 mice (Chow) and mice fed high-fat diet (HFD) for 15 weeks were used as controls. n = 3–6 per group. Data are presented as mean ± SEM. **P<0.01, ***P < 0.001, ****P < 0.0001 as analysed by two-way (A–N) or one-way (O) ANOVA followed by Bonferroni post hoc test or two-tailed unpaired Student’s t-test (A).