Endocrine Abstracts

Calcium ion is important for physiological functions in all tissues and organs, and is essential for many vital functions. Calcium in lumen is absorbed to cytosol, and Calbindin-D9k binds calcium. It can remove calcium to extracellular through PMCA1 and NCX1. However, in the rat esophagus, the calcium related gene regulations and localizations were not well documented. We evaluated calcium related genes including Calbindin-D9k, PMCA1, and NCX1. Immature rats were daily treated for three days with estradiol, progesterone and vehicle as control. To evaluate the pathway, antagonist groups were treated with ICI 182,780 and RU486 before 30min ahead on hormone administration. The mRNA level of Calbindin-D9k, PMCA1, and NCX1 were quantified by qPCR, protein level and localization of Calbindin-D9k, PMCA1, and NCX1 in the esophagus were identified by immunofluorescence. Calbindin-D9k expression was increased by E2 and not altered by P4. ICI decreased Calbindin-D9k expression induced by E2, but no effect was observed in RU compare with P4. PMCA1 expression was shown as opposed to the Calbindin-D9k expression. PMCA1 mRNA was decreased by E2 and not altered by P4. ICI recovered PMCA1 expression inhibited by E2. Similarly, NCX1 mRNA expression was decreased only by E2. Calbindin-D9k and PMCA1 were mainly localized in mucosa layer. The main site of the NCX1 expression was muscularis externa. Calcium related gene expressions were affected by steroid hormones in esophagus similar with previous studies. Study for regulation factor for Calcium related genes other than steroid hormone is further needed.