Figure 1.

Gene expression of (A) orexigenic (Agrp and Npy) and (B) anorexigenic (Cart and Pomc) related genes measured by qRT-PCR in the hypothalamus of rats of different ages (from 1 to 6 months) housed at different room temperatures: 22°C (control) or 4°C for 1 week (cold). Results represent mean ± SEM (n = 5–6) of ratios of specific mRNA levels relative to Gdi, expressed as a percentage, where the 1-month control group was set as 100%. The orexigenic/anorexigenic ratio (C) was calculated as the sum of the expression of the orexigenic peptide (Agrp and Npy) genes divided by the sum of the expression of the orexigenic peptide (Cart and Pomc) genes. Bars not sharing common letters (a,b,c) are significantly different (one-way ANOVA, p < 0.05). DMS post-hoc was used after one-way ANOVA analysis. ^*Effect of cold exposure (cold-exposed rats vs. their respective controls; Student's t-test, p < 0.05, or indicated when different). Two-way ANOVA (p < 0.05) was performed for cold and control conditions (T) and age (A). For this statistical analysis: T indicates effect of temperature, A effect of age, and T^*A the interaction of temperature and age.