Figure 4.

Drp1 KI mice display higher lipid utilization and respiratory capacity

(A and B) WT and Drp1 KI male mice fed on a LFD were used to analyze body weight (A) and composition (B) through EchoMRI.

(C) Total activity was measured during indirect calorimetry tests using a comprehensive laboratory animal monitoring system (CLAMS).

(D) Intraperitoneal glucose tolerance test (2 g/kg) performed on WT and Drp1 KI mice fasted for 12 h.

(E) Intraperitoneal insulin tolerance test performed on WT and Drp1 KI mice fasted for 6 h. Insulin (0.5 U/kg) was injected and glycemia was recorded for the time points indicated.

(F and G) Respirometry analyses of uncoupled (leak) respiration, complex I (CI) respiration, complex I + complex II (CI+CII) respiration, maximal electron transport system (ETS) capacity, and maximal complex II (CII)-driven respiration in liver (F) and BAT (G) homogenates from WT and Drp1 KI mice.

(H and I) Total O₂ consumption (VO₂) (H) and respiratory exchange ratio (RER) (I) in WT and Drp1 KI mice were measured through indirect calorimetry.

All values are presented as mean ± SEM of n = 10 WT and n = 11 Drp1 KI mice. Differences between the two groups were analyzed using a Student’s two-tailed t test in (A)–(C), (F), and (G). Linear mixed-effect models were used in (D), (E), (H), and (I) to assess time × group interaction effects; subsequent comparisons were performed with Tukey’s honest significant difference post hoc test. ^∗p < 0.05, ^∗∗p < 0.01, and ^∗∗∗p < 0.001 between the designated groups. See also Figure S4.