Endocrine Abstracts

Introduction: Calbindin-D9k (CaBP-9k), which is a calcium ion buffering and transporter gene, is known to be regulated by the vitamin D and steroid hormones, and is mainly expressed in mammalian intestine, kidney and uterus. However, CaBP-9k expression in lung has not been studied. Maintaining lung structure using pulmonary surfactant is important for pulmonary gas exchange. Steroids are known to accelerate maturation of the fetal lung and secretion of surfactant. Otherwise the relationship between pulmonary function especially in surfactant secretion and CaBP-9k expression has not been researched. In this study, we investigate the CaBP-9k expression by sex steroid hormones and glucocorticoids in mouse lung.

Materials and methods: To confirm the effect of sex steroid hormones, the immature mice age from 14 days to 16 days were respectively injected of estrogen (E₂) and progesterone (P₄) for 3 days. To confirm the effect of glucocorticoids, the mature mice age from 11 weeks were respectively injected of dexamethasone (Dex). ER antagonist (ICI187,780) and PR, GR antagonist (RU486) were injected 30 min prior to steroid hormones. We compared the changes in the CaBP-9k expression of each group using polymerase chain reaction.

Results: In the estrogen and progesterone treated immature mice lung, the CaBP-9k gene expression had no significant change in mRNA and protein level but significantly increased in Dex treated mice lung. It is suggested that glucocorticoids may play a role in regulation of CaBP-9k expression in lung.

Conclusion: Our results has significance to the regulation of CaBP-9k by Dex. By studying the effects on lung surfactant through the control of CaBP-9k, it may be presented as a basis data of pulmonary surfactant associated disease or research.