C1q/tumor necrosis factor 5 (CTRP5 or C1QTNF5) is a member of the C1q/tumor necrosis factor superfamily. Mutations in this gene are associated with late-onset retinal degeneration (LORD). CTRP5 is also abundantly expressed in adipose tissue and circulates in the blood. It is secreted as a glycoprotein, initially forming trimers then higher order oligomeric complexes. Extracellular, recombinant CTRP5 is a potent activator of AMP-activated protein kinase (AMPK), leading to increased cell surface recruitment of GLUT4 and increased glucose uptake. Serum CTRP5 levels are significantly elevated in obese or diabetic mice. Cayman's CTRP5 (human) EIA Kit is a competitive assay which can be used to measure CTRP5 in human serum or plasma. The assay exhibits a detection limit of 2.3 ng/ml and an assay range of 2.3-5,000 ng/ml.