Figure 3. Ascorbic acid induces the expression of salivary gland functional proteins involved in saliva secretion. SAMP1/kl -/- mice were fed daily with ascorbic acid (100 mg/kg). (A–D) α-amylase, aqua4/5, and ZO-1 expression in the salivary glands of SAMP1/ kl-/- mice was analyzed by quantitative RT–PCR or Western blotting. *p < 0.05, **p < 0.01. (E) Immunohistochemistry staining of α-amylase, aqua4/5, and ZO-1 in submandibular or sublingual tissue of salivary glands from ascorbic acid-treated SAMP1/ kl -/- mice. (F) After oral administration of ascorbic acid in SAMP1/kl-/- mice, saliva was stimulated with an acetylcholine injection at 7 or 12 days. (G) Serum Ca2+ levels in the control and ascorbic acid-treated SAMP1/kl-/- mice at the indicated times. *p < 0.05. Data are presented as the mean ± standard deviation (SD). Each group was compared with the mean of the control.