Table 3. Body weight and composition in male rats before and after 21 days of 50% calorie restriction (CR), and after 14 days of ad libitum recovery from CR; Mean (SEM).
| Genotype | Baseline |
Calorie restriction |
CR-induced change |
||||||
|---|---|---|---|---|---|---|---|---|---|
| BW (g) | Fat mass (g) | Lean mass (g) | BW (g) | Fat mass (g) | Lean mass (g) | Fat mass (g) | Lean mass (g) | % BW lost | |
| Mc4rK314X/K314X | 705.46*,† (22.25) | 263.50*,† (10.06) | 389.68*,† (13.31) | 629.66*,† (17.62) | 198.49* (6.53) | 364.38*,† (11.69) | −65.01*,† (5.61) | −25.31*,† (2.27) | −10.67*,† (0.46) |
| Mc4r+/K314X | 505.16 (11.70) | 103.37* (7.26) | 353.32 (5.12) | 431.34 (12.54) | 51.40* (5.64) | 319.66 (7.20) | −51.98 (2.10) | −33.66* (2.87) | −14.96* (0.57) |
| Mc4r+/+ | 500.68 (9.79) | 80.78 (2.27) | 368.45 (7.44) | 415.34 (9.16) | 33.98 (1.77) | 320.21 (6.59) | −46.80 (1.79) | −48.24 (2.21) | −17.06 (0.62) |
| Ad libitum-fed recovery from CR | Recovery-induced increase from CR | Recovery-induced increase relative to baseline | |||||||
| BW (g) | Fat mass (g) | Lean mass (g) | Increase in BW (g) | Increase in fat mass (g) | Increase in lean mass (g) | Change in BW (g) | Change in fat (g) | Change in lean mass (g) | |
| Mc4rK314X/K314X | 708.04*,† (21.56) | 233.41*,† (8.01) | 401.35*,† (14.65) | 78.39 (4.81) | 34.93 (2.78) | 36.98* (3.22) | 2.59 (3.86) | −30.08*,† (3.26) | 11.67* (3.01) |
| Mc4r+/K314X | 509.11 (12.26) | 84.23* (6.31) | 359.94 (6.39) | 77.76 (3.28) | 32.84 (1.76) | 40.27 (2.45) | 3.95 (3.31) | −19.14 (2.08) | 6.61 (2.16) |
| Mc4r+/+ | 498.68 (8.13) | 62.86 (1.91) | 368.46 (7.44) | 83.33 (3.29) | 28.89 (1.83) | 48.26 (2.64) | −2.00 (4.09) | −17.92 (2.86) | 0.02 (1.97) |
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 = 8).
BW: Body weight.
*significantly different from Mc4r+/+; †significantly different from Mc4r+/K314X; p < 0.05.