The generation of Metrnl global knockout mice (Metrnl−/−) and the effects of global knockout of Metrnl on blood lipid parameters under a normal chow diet. a Knockout strategy (left) and breeding strategy (right) for Metrnl−/−. b Genotyping of the Metrnl−/− mice. 1, Metrnlwt/koElla-Cre; 2, Metrnlwt/ko; 3, Metrnlwt/wt; 4, Metrnlko/ko (Metrnl−/−). c Metrnl levels in different tissues between Metrnl−/− and wild-type mice (WT) (n = 6). ***P < 0.001 vs. WT. d Serum Metrnl concentration between Metrnl−/− and WT mice (n = 6). e Body weights of Metrnl−/− and WT mice fed a normal chow diet (n = 8). f The effects of global knockout of Metrnl on high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), total triglyceride (TG) and nonesterified fatty acid (NEFA) in circulation (n = 8)