Sex-based differences in Smgc expression in the submandibular gland of C57BL/6 mice

Abstract

Objective: The decrease in female hormone levels at menopause affects whole-body homeostasis. Various therapies including hormone therapy and treatment with herbal supplements are available to improve menopausal symptoms. However, a method for evaluating their effectiveness has not been established. We sought to identify useful biomarkers to assess therapy efficacy. Methods: We searched for salivary proteins affected by changes in female hormone levels in mouse submandibular glands. Results: The expression of submandibular gland protein C (Smgc) was decreased following ovariectomy, while the expression of the alternative splicing transcript t-Smgc was increased. Notably, Smgc expression increased following β-estradiol administration, and was barely detectable in the submandibular glands of male mice. Conclusion: The results suggest that Smgc expression may be estrogen dependent. Moreover, changes in the SMGC protein amount in the saliva were in accordance with those in mRNA expression in the submandibular gland. Our findings suggest that salivary proteins have potential as markers for evaluating therapies for menopausal symptoms.