Nuclear receptors: doubling up in the lung.

Inhaled corticosteroids are highly effective in the treatment of asthma and also show efficacy in chronic obstructive pulmonary disease (COPD). Considerable effort continues to be focused on improvement of their pharmacology and pharmacokinetic properties. Corticosteroids act through the glucocorticoid receptor, one of a family of ligand activated transcription factors. These proteins are highly tractable to drug discovery, and are targeted by a number of existing therapeutic agents. The possibility that family members other than the glucocorticoid receptor might have therapeutic benefit in lung disease has received increasing attention. Recent studies using ligands for the vitamin D3 receptor, the peroxisome proliferator-activated receptors, and the liver X receptor have demonstrated significant potential for these novel targets in the treatment of lung disease.