Table 1. Body composition and calorimetry measures from measurement of 24-hr energy expenditure (EE), and activity-EE (treadmill test); Mean (SEM).
| Genotype | Body Weight (g) | Lean Mass (g) | Fat Mass (g) | % Fat | % Lean | VO2 (ml/kg/hr) | VCO2 (ml/kg/hr) | EE (kcal/hr) | Horizontal Activity (counts/min) | Ambulatory Activity (counts/min) | Vertical Activity (counts/min) | Treadmill EE (kcal/hr) |
Treadmill RER |
|||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Resting EE | Total activity EE | Activity EE-resting EE | Last 90 min of rest | Total 30 min of activity | ||||||||||||
| Mc4rK314X/K314X | 339.55*,† (8.77) | 223.63*,† (5.56) | 65.48*,† (3.86) | 20.04*,† (0.78) | 68.80*,† (0.79) | 1588*,† (16.44) | 1580 (21.36) | 2.72*,† (0.07) | 5.01*,† (0.21) | 2.31* (0.13) | 0.21*,† (0.02) | 2.37 (0.06) | 5.67 (0.29) | 3.30 (0.27) | 0.87 (0.01) | 0.90 (0.01) |
| Mc4r+/K314X | 245.24 (7.78) | 183.51 (3.16) | 25.82 (1.52) | 10.77 (0.64) | 76.53 (1.07) | 1743 (26.85) | 1671 (32.79) | 2.14 (0.04) | 6.12 (0.26) | 2.68 (0.13) | 0.35 (0.02) | 1.93 (0.05) | 4.52 (0.16) | 2.59 (0.17) | 0.87 (0.82) | 0.90 (0.01) |
| Mc4r+/+ | 244.88 (8.31) | 183.88 (6.36) | 24.86 (1.28) | 10.67 (0.51) | 78.72 (0.34) | 1684 (31.15) | 1679 (42.12) | 2.14 (0.06) | 6.72 (0.16) | 2.98 (0.11) | 0.36 (0.02) | 1.97 (0.14) | 4.57 (0.18) | 2.60 (0.23) | 0.82 (0.02) | 0.87 (0.01) |
Male rats homozygous (Mc4rK314X/K314X, n = 8) or heterozygous (Mc4r+/K314X, n = 8) for non-functional melanocortin 4 receptor (MC4R), or wild-type rats (Mc4r+/+, n = 6). RER, respiratory exchange ratio (VCO2/VO2).
*significantly different from Mc4r+/+; †significantly different from Mc4r+/K314X; p < 0.05.