Lung type II cell and macrophage annexin I release: differential effects of two glucocorticoids

Annexin I (lipocortin 1) is abundant in lung secretions. Concentrations ris e after oral glucocorticoid, but the effect of inhaled budesonide on annexi n I release is unknown. Extracellular annexin I in bronchoalveolar lavage f luid (BALF) from 11 asthmatic patients was unaffected by inhaled budesonide (800 mu g twice daily for 4 wk; mean after budesonide, 110 ng/mg albumin; after placebo, 107 ng/mg albumin). Rat alveolar macrophages (AMs) and alveo lar epithelial type II (ATII) cells were cultured alone and with budesonide or dexamethasone. Mean basal concentrations of cellular (3.5 ng/10(6) AMs; 4.4 ng/10(6) ATII cells) and secreted (1.4 ng/10(6) AMS; 1.8 ng/10(6) ATII cells) annexin I were similar in AMs and ATII cells. Although budesonide s ubdued annexin I secretion from both cell types, dexamethasone stimulated a nnexin I release. Annexin I release from ATII cells peaked at 10(-7) M dexa methasone but at 10(-3) M dexamethasone from AMs. Thus, at low concentratio ns of dexamethasone, ATII cells probably contribute more annexin I to respi ratory tract secretions than AMs, although at high concentrations, both cel ls probably contribute. The study demonstrates previously undescribed diffe rences between glucocorticoids and between AMs and ATII cells with respect to annexin I regulation.