Figure 5.

Blunted circadian amplitude of spontaneous water intake in female Ucn-2 mutant mice. a, b, A 24 h profile of water intake showed decreased peak water intake at the onset of the dark cycle and a trend for increased water intake at the diurnal nadir in female, but not male, Ucn-2 null mice. c, d, In contrast, the circadian profile of eating was not reliably altered in Ucn-2 null mutant mice of either sex. e, f, Female, but not male, Ucn-2 null mutant mice showed a flattening of the circadian rhythm of the water/food ratio, in which rodents typically drink in greater quantities relative to food during the nocturnal compared with diurnal cycles. Split-plot ANOVA revealed significant genotype × time interactions for the time course of drinking (F_(7,70) = 2.17; p < 0.05) and water/food ratios (p < 0.05) in female, but not male, mice. Table 1 further quantifies differences in the circadian profile of ingestion using cosinor analysis. Data are displayed as the mean ± SEM, and the black bar represents the dark cycle. *p < 0.05 vs WT condition (Student’s t test).