Table 2. Thermogenic properties in liver, brown adipose tissue and hormones in tree shrews under different seasons.

	Spring (n = 8)	Summer (n = 10)	Autumn (n = 9)	Winter (n = 8)	F
Body mass	117.6 ± 5.8b	105.4 ± 4.8c	112.7 ± 2.6b	125.69 ± 4.3a	3.46*
Brown adipose tissue
Mass (g)	0.57 ± 0.07b	0.43 ± 0.07c	0.52 ± 0.06b	0.63 ± 0.05a	2.98*
% body mass	0.48 ± 0.03	0.41 ± 0.02	0.46 ± 0.07	0.50 ± 0.06	0.96ns
TP (mg·g−1)	26.41 ± 1.20a	17.39 ± 0.97c	21.36 ± 1.02b	28.44 ± 0.81a	4.21**
MtP (mg·g−1)	10.21 ± 0.94ab	6.92 ± 1.02c	9.58 ± 0.84b	12.98 ± 0.95a	2.98*
ST4 (nmol O2 mg−1 MtP min−1)	9.89 ± 0.45	8.62 ± 0.15	9.11 ± 0.36	10.95 ± 0.26	3.06*
UCP 1 (RU/total BAT tissue)	1.29 ± 0.45b	1.00 ± 0.21c	1.36 ± 0.19b	1.68 ± 0.36a	3.11*
COX (μg atoms Omin−1 mg−1 MtP)	925.6 ± 123.1b	468.5 ± 89.1d	795.6 ± 89.3c	1216.4 ± 112.3a	4.69**
T4 5′-D II (pmol O2 ·mg−1 ·MtP min−1)	33.48 ± 3.5b	27.60 ± 2.9c	31.98 ± 1.9b	39.48 ± 3.1a	3.85*
Liver
Mass (g)	5.32 ± 0.36ab	4.67 ± 0.48bc	5.03 ± 0.24b	5.78 ± 0.56a	3.42*
% body mass	4.45 ± 0.27	4.43 ± 0.26	4.46 ± 0.31	4.60 ± 0.15	2.46ns
TP (mg·g−1)	91.25 ± 0.47b	82.81 ± 3.26d	86.59 ± 0.64c	97.52 ± 4.23a	3.48*
MtP (mg·g−1)	33.61 ± 0.21b	28.41 ± 1.95c	34.11 ± 0.22b	38.33 ± 2.11a	3.01*
ST4 (nmol O2 mg−1 MtP min−1)	27.27 ± 0.96b	24.57 ± 1.01c	25.98 ± 0.84c	29.25 ± 1.48a	3.74*
COX (μg atoms O min−1 mg−1 MtP)	79.24 ± 3.12b	76.64 ± 4.31c	80.14 ± 2.11b	85.02 ± 2.36a	3.65*
Hormones
Tri-iodothyronine (T3, ng·ml−1)	1.13 ± 0.13ab	0.74 ± 0.08c	0.98 ± 0.11b	1.38 ± 0.19a	4.15*
Thyroxine (T4, ng·ml−1)	16.12 ± 0.68	16.70 ± 0.62	15.21 ± 0.56	14.79 ± 0. 61	1.96ns
T3/T4 (×100)	7.01 ± 0.22b	4.43 ± 0.30d	6.44 ± 0.19c	9.33 ± 0.28a	5.13**
Thyroid-stimulating hormone (TSH, ng·ml−1)	0.83 ± 0.09	0.85 ± 0.08	0.79 ± 0.15	0.75 ± 0.11	0.95ns

Different superscripts in each row means significantly different (Tukey’s post hoc test, α = 0.05; a > b > c) among seasons.

Statistical analyses: ^*P < 0.05, ^**P < 0.01, ^nsP > 0.05.