Table 2.

Motor activity of interleukin-18 knockout (IL-18 KO) and wildtype mice during the fast-refeed protocol

	Horizontal Activity				Vertical Activity
	Fasting		Feeding		Fasting		Feeding
	Low-Fat	High-Fat	Low-Fat	High-Fat	Low-Fat	High-Fat	Low-Fat	High-Fat
Dark cycle
IL-18 KO	25.3 ± 2.9	20.0 ± 2.5	17.5 ± 2.5	18.1 ± 1.9	5.2 ± 1.3	4.5 ± 1.7	3.3 ± 1.0	4.0 ± 1.5
Wildtype	31.8 ± 5.8***	19.4 ± 2.7	13.2 ± 2.3	23.9 ± 2.2##	6.5 ± 1.5**	3.6 ± 0.7	2.0 ± 0.6	4.5 ± 0.5#
Light cycle
IL-18 KO	6.0 ± 1.2	9.7 ± 0.9	6.0 ± 0.9	15.3 ± 1.7	1.4 ± 0.3	1.4 ± 0.4	1.6 ± 0.3	1.8 ± 0.4
Wildtype	6.1 ± 1.7***	10.6 ± 1.2	6.0 ± 1.0	16.7 ± 2.4##	2.0 ± 0.7**	0.9 ± 0.2	2.2 ± 0.6	2.9 ± 0.8

Data express M (±SEM) photocell interruptions (x100) in the x-dimension (horizontal activity) or z-dimension (vertical activity) in mature female IL-18 knockout (KO) mice (n = 7) and their wildtype controls (n = 6) during a 3-hr fasting period and a subsequent 3-hr refeeding period. In each subject, the fast-refeed protocol was performed during both the dark and light cycle and while receiving low-fat or high-fat diet. Potential genotype effects on motor activity could not account for differences in energy expenditure, because mice expended less energy even during periods when IL-18 KO mice moved as much as or more than WT mice. The only significant effect involving Genotype was a Genotype × Diet × Fasting interaction. Post hoc deconvolution of this interaction, shown as symbols in the Table, indicated that wildtype mice moved significantly less during the feeding vs. fasting period in low-fat diet testing, but more in the feeding vs. fasting period during high-fat diet testing, and the corresponding differences were smaller or absent in IL-18 KO mice. Irrespective of genotype, mice moved significantly more during the dark cycle (than light cycle), especially during the fasting (vs. feeding) phase of testing (see Results for statistics). Symbols represent

^**p < 0.01,

^***p < 0.001 greater than wildtype mice fasting from high-fat diet or feeding on low-fat diet;

^#p < 0.05,

^##p < 0.005 greater than wildtype mice feeding on low-fat diet or fasting from high-fat diet.