Estrogen Effect on the Na,K-ATPase Activity Repressed by IgE-Dependent Histamine-Releasing factor in HeLa Cells

IgE-dependent histamine-releasing factor (HRF) is found extracellularly to regulate the degranulation process of histamine in mast cells and basophils and known to play a predominant role in the pathogenesis of chronic allergic disease. HRF has been also identified in the intracellular region of the cell. Previously, we reported that HRF interacts with the 3rd cytoplasmic domain of the alpha subunit of Na,K-ATPase and inhibits Na,K-ATPase activity. Since it is known that estroaen activates the sarcolemmal Na,K-ATPase, we tested whether estrogen recovers the Na,K-ATPase activity repressed by HRF. In this study, we showed that estrogen activates Na,K-ATPase repressed by HRF. RT-PCR and western blot analysis showed that estrogen doesn't reduce the expression level of HRF in HeLa cell, suggesting that this recovery effects of estrogen probably occur via indirect mechanism on HRF and Na,K-ATPase.