Androgen Regulation of SMR2 Gene Expression in Rat Submandibular Gland: Evidence for a Graded but not a Binary Response

• Published in: The journal of histochemistry and cytochemistry 2003-10, Vol.51 (10), p.1317-1329
• Main Authors: Huaulme, Jean-Francois, Courty, Yves, Rougeon, Francois, Rosinski-Chupin, Isabelle
• Format: Article
• Language: English
• Subjects: Androgens - metabolism; Androgens - pharmacology; Animals; Animals, Newborn - metabolism; Blotting, Northern; Female; Gene Expression Profiling; Gene Expression Regulation - drug effects; Gene Expression Regulation - physiology; In Situ Hybridization; Isoproterenol - pharmacology; Male; Poly A - metabolism; Pregnancy; Protein Biosynthesis; Proteins; Rats; Rats, Wistar; RNA, Messenger - biosynthesis; RNA, Messenger - genetics; Salivary Proteins and Peptides - biosynthesis; Salivary Proteins and Peptides - genetics; Sex Factors; Submandibular Gland - cytology; Submandibular Gland - drug effects; Submandibular Gland - metabolism; Submandibular Gland - physiology; Time Factors
• ISSN: 0022-1554; 1551-5044
• DOI: 10.1177/002215540305101009

Expression of SMR2, a member of the gene family encoding salivary glutamine/glutamic acid-rich proteins, is regulated by androgens in rat submandibular gland acinar cells. To further characterize SMR2 regulation, we analyzed SMR2 expression during submandibular gland postnatal development and rat puberty at both a global and a single-cell level. Using in situ detection of mature and primary SMR2 transcripts, we show that SMR2 expression is heterogeneous among acinar cells. However, only one cell population with various amounts of mRNAs can be defined. The number of high-expressing cells increases in males during puberty and in females up to 6 weeks of age, suggesting that some factor in addition to acinar differentiation might be important for SMR2 expression in female rats. Involvement of the β-adrenergic system in regulating SMR2 expression was tested in rats exposed daily to isoproterenol for 4 days. Under these conditions we found an increase in SMR2 expression in female rats, associated with an increase in SMR2 mRNA levels in most acinar cells. This suggests that a signaling cascade, elicited by β-adrenergic stimuli, might act in concert with androgens to regulate SMR2 expression.