Figure 6.

Growth curves, fat mass, and plasma leptin levels of individually housed Pomc^+/+Tg⁺, Pomc^–/–, and Pomc^–/–Tg⁺ mice from ages 5 to 15 weeks. (A) The effect on body weight of pair-feeding (PF) of Pomc^–/–Tg⁺ mice to the daily food intake of Pomc^+/+Tg⁺ mice starting at age 5 weeks (n = 5–11). Repeated-measures ANOVAs over the 10-week period showed a main effect of group for males (F_18,117 = 21.5, P < 0.0001) and females (F_18,144 = 24.6, P < 0.0001). One-factor ANOVAs showed that Pomc^–/–Tg⁺ pair-fed mice differed from Pomc^–/–Tg⁺ mice fed ad libitum and Pomc^+/+Tg⁺ mice fed ad libitum (P < 0.001); Pomc^–/– mice fed ad libitum also differed from Pomc^+/+Tg⁺ mice fed ad libitum and Pomc^–/–Tg⁺ mice fed ad libitum (P < 0.001) but not from Pomc^–/–Tg⁺ pair-fed mice. (B) The effects of pair-feeding of Pomc^–/–Tg⁺ mice on accumulation of fat mass. The combined weight of 4 white fat pads (renal, visceral, gonadal, and inguinal) was different among groups in 15- to 20-week-old male (F_3,17 = 50.3, P < 0.0001) and female (F_3,23 = 35.9, P < 0.0001) mice. *P < 0.05, **P < 0.001, and ***P < 0.0001 compared with Pomc^+/+Tg⁺; ^#P < 0.0001 compared with Pomc^–/–Tg⁺. (C and D) The effect of pair-feeding of Pomc^–/–Tg⁺ mice on plasma leptin levels. Data are the means and scattergrams of all individual leptin levels (n = 9–19) obtained after a 16-hour overnight fast in 9-week-old (C) and ad libitum–fed 15- to 20-week-old (D) mice of both sexes.