HPGD, or 15-hydroxyprostaglandin dehydrogenase, is a NAD+-linked dehydrogenase that oxidizes the hydroxyl group at position 15 of prostaglandins to a ketone, resulting in a loss of biological activity. HPGD is a major enzyme for the catabolism of prostaglandins. The enzyme is a member of the short-chain alcohol dehydrogenase family of enzymes. HPGD is a cytosolic enzyme expressed in most tissues, with highest expression levels in placenta, lung, and kidney. It is inhibited by aspirin and nonsteroidal anti-inflammatory drugs. Defects in HPGD are a cause of hypertrophic osteoarthropathy.