Diminished hypertrophic response of PKD1 cKO mice to ISO infusion. (A) Hearts of WT and PKD1 cKO mice chronically infused with either saline vehicle (WT and PKD1 cKO; n = 6) or isoproterenol (8.7 mg/kg per day) for 7 days (Top; n = 11; PKD1 cKO, n = 16), histological sections stained with H&E (Middle) or Masson's trichrome to detect fibrosis (Bottom). (Scale bars: Top and Middle, 2 mm; Bottom, 40 μm.) (B) Heart weight/tibia length (HW/TL) ratios (±SEM) are shown as bar graphs (n = 7–9). (C) Transcripts for markers of hypertrophy in hearts from WT and PKD cKO mice infused with either saline vehicle or isoproterenol. Values indicate relative expression level to a WT sham-operated group (±SEM). ANF, atrial natriuretic factor; β-MHC, β-myosin heavy chain; Col1α2, procollagen, type I, α2.