It causes cortisol levels to rise.......But its also an anti-cortisol !
Several factors are now understood. RU486 will itself suppress the immune system by causing the patient’s cortisol to rise. Cortisol, a glucocorticoid hormone, acts to suppress the immune system by diminishing the ability of certain white blood cells (leukocytes) to migrate to sites of tissue infection; acts to suppress lymphocyte (another type of white blood cell) gene expression; and acts on neutrophils (another type of white blood cell) capacity to kill ingested bacteria cells (thus blocking this white blood cells’ capacity to stop infection). All of these effects hinder the immune systems capacity to fight off bacterial infection.
See these studies.....
Bertagna et al, The new Steroid Analog RU486 Inhibits Glucocorticoid Action in Man, J. Clin. Endocrinol. Metab., 59, 1, 1984, 25-28.
Schulster et al, Molecular Endocrinology of the Steroid Hormones, 1976, New York, John Wiley & Sons, 282.