Binds phosphatidylcholine, phosphatidylinositol, polychlorinated biphenyls (PCB) and weakly progesterone, potent inhibitor of phospholipase A2. Antiparallel homodimer; disulfide-linked (By similarity). Interaction with LMBR1L is controversial (By similarity). Clara cells (nonciliated cells of the surface epithelium of the pulmonary airways). Appears on the eighteenth day of gestation in the airway epithelium. By glucocorticoids. Belongs to the secretoglobin family.