Figure 1: Skeletal muscle hypertrophy caused by GR ablation in skeletal muscle.

(a) Body weight of ad libitum-fed male (solid lines) and female (dotted lines) GRf/f (blue), GRmKO (red) and GR^flox/+ACTA1-Cre⁺ (hetero GRmKO, green) mice. Error bars represent mean±s.e.m. (n=16). *P<0.05 between GRf/f and GRmKO; ^†P<0.05 between GRmKO and hetero GRmKO determined by two-tailed Student’s t-test for unpaired data. (b) Representative photographs of 18-week-old male GRf/f and GRmKO mice. (c) Representative computed tomography (CT) coronal section images of 18-week-old male GRf/f and GRmKO mice. Fibulae are indicated as f. (d) Weight of tissues from 20-week-old male GRf/f and GRmKO mice. Data are shown as boxplots of ratio to body weight (n=16). Muscles are abbreviated as Gas (gastrocnemius), TA (tibialis anterior), Sol (soleus), EDL (extensor digitorum longus) and PT (plantaris). Whiskers show the minimum and maximum of all the data, boxes show one standard deviation above and below the mean of the data, and lines inside the boxes show the median of the data. *P<0.05; **P<0.01 determined by two-tailed Student’s t-test for unpaired data. NS, not significant. (e) Representative images of immunostaining for type IIb, IIa and I myosin heavy chain (red in the panels indicated as MyHC IIb, MyHC IIa and MyHC I, respectively) and type IV collagen (green) of serial transverse cryosections of Gas from 20-week-old male GRf/f and GRmKO mice. Scale bars represent 100 μm. (f) Myofibre cross-sectional area (CSA) distribution in Gas from 20-week-old male GRf/f (blue) and GRmKO (red) are shown as frequency histograms (300<n<330, from three independent animals of each genotype).