Figure 2. Daily expression profiles of the salivary-gland-characteristic genes in the submandibular glands. After mice were housed under 12:12-hour LD conditions for 19 days, expression levels (mean ± SEM, n = 3) of mRNAs for amylase 1 (Amy1), mucin 10 (Muc10), cystatin C (Cst3), and epidermal growth factor (Egf) were determined in the presence or absence (dotted lines) of foods. Foods were withheld at ZT0 on day 19, and the mice were killed at the indicated zeitgeber time (ZT—recorded in hours) on day 20. P-values without or within parentheses (the starved group) are shown in the panel. Fasting altered the expression profile of Amy1 mRNA, but it did not induce circadian rhythms of other salivary-gland-characteristic genes.