Fig 2: Circulating factors mediate impaired liver GH signaling in cardiac aKO?KO mice A, BPhosphorylated and total STAT5 in WT mouse primary hepatocytes treated with DMEM (control), 50% plasma in DMEM (A), or 50% plasma fractions in DMEM (B) for 1 h were determined by Western blot. ß-Actin is used as loading control in all Western blots. Source data are available online for this figure.

Fig 3: Cardiac aKO?KO mice exhibit FTT with impaired liver GH signaling ADaily body weight of aKO?KO and littermate control mice. n = 55–145 mice per group with both genders included.BRepresentative picture of 10-day-old aKO?KO and littermate control aHet?WT mice.C, DPlasma GH and IGF1 concentrations in 10- (C, n = 7–10 mice per group) and 16-day-old mice (D, n = 9–11 mice per group) measured by ELISA.EPhosphorylated (Tyr694) and total STAT5 in 10-day-old mouse livers determined by Western blot (n = 3–4 mice per group). ß-Actin serves as a loading control.FRelative levels of phosphorylated and total STAT5 and JAK2 in 13-day-old mouse livers (normalized to total protein content of individual mouse liver) were quantified by ELISA (n = 13 mice per group).GExpression of STAT5 target genes Igf1, Igfbp3, and Igfals in 10-day-old mouse livers measured by qPCR (n = 7–8 mice per group).HLiver (normalized to total protein content, n = 15–16 mice per group) and plasma (n = 9–10 mice per group) IGFBP3 concentrations in 13-day-old mice measured by ELISA.Data information: *P < 0.05, **P < 0.01, ****P < 0.0001, *****P < 0.00001, and ******P < 0.000001 between aKO?KO and all other control genotypes by t-test. All values are mean + s.e.m. Source data are available online for this figure.

Fig 4: GDF15 is a bona fide heart-derived hormone that regulates liver GH signaling ADesign of AAV9-mGDF15 shRNA construct to specifically knockdown GDF15 in Cre+ cardiomyocytes.B–GCardiac Gdf15 expression quantified by qPCR (B), plasma GDF15 concentrations measured by ELISA (C), cardiac Bnp expression quantified by qPCR (D), liver phosphorylated STAT5 level measured by ELISA (E), and plasma IGF1 (F) and GH concentrations (G) measured by ELISA in 9- to 10-day-old littermate control and aKO?KO mice (n = 8–12 mice per group) that received pericardial injection of AAV9-control or Gdf15 shRNA at 2 days of age. *P < 0.05, **P < 0.01, and ***P < 0.001 by t-test. Values are mean + s.e.m.