Helen Christian's research interests are in the mechanisms of steroid hormone regulation of the pituitary gland, in particular the role of Annexin 1. The Annexins are a well-conserved super-family of structurally related Ca2+ - and phospholipids-binding proteins with wide-ranging functions in health and disease. Annexin 1 is a 37kD protein that is induced by glucocorticoids and mediates glucocorticoid action within the host defence and neuroendocrine systems. Glucocorticoids regulate the synthesis, phosphorylation and cellular disposition of annexin 1, and annexin 1 is implicated in the regulation by these important drugs of pituitary function, the control of cell growth and signal transduction. Most recently her group have characterized a novel secretory pathway of annexin 1, a protein which lacks a signal sequence, involving a member of the ATP binding cassette transporter family, ABCA1. This is the first time the secretion mechanism of an annexin family member has been determined and the group are interested in whether similar pathways may be utilized by other annexin family members. Also the group have demonstrated regulation of annexin 1 expression by estrogens. This is exciting, as gender differences in annexin 1 regulation may underly differences between the sexes in regulation of the hypothalamo-pituitary-adrenal axis and susceptibility to immune and inflammatory diseases.