Expression from the HIV-LTR is stimulated by glucocorticoids and pregnancy.

Gene regulation in several retroviral systems is subject to steroid hormone control. Clinical studies have shown that the human immunodeficiency virus (HIV) core protein p24 is more readily detectable in infected women during pregnancy. Here we show that expression of the HIV long terminal repeat (LTR) is induced by glucocorticoids in tissue culture cells and by pregnancy in placental and uterine tissue of transgenic mice. We suggest that hormonal stimulation could influence proviral activation and that placental expression of the HIV-LTR could contribute to the high perinatal transmission rate of HIV.