Vitamin D-binding protein (VDBP), also known as GC globulin, is a 58 kDa glycoprotein primarily synthesized and secreted by the liver. It plays a critical role in the transport and regulation of vitamin D metabolites, binding approximately 85% to 90% of circulating 25-hydroxyvitamin D2/3 and 1,25-dihydroxyvitamin D3. Only a small fraction of these metabolites—less than 1%—remain in free form within the bloodstream. VDBP ensures that vitamin D is bioavailable and effectively delivered to target organs, playing a key role in calcium homeostasis and bone metabolism.
In addition to its role in vitamin D transport, VDBP has a secondary function in binding extracellular actin released during tissue injury, forming DBP-actin complexes that are then cleared by the kidneys. This actin scavenging system is crucial during conditions such as trauma, sepsis, or multiple organ failure, where VDBP levels tend to drop. Low serum VDBP may therefore serve as a clinical indicator of systemic inflammation or tissue damage.
Clinically, urinary VDBP has emerged as a potential biomarker for predicting major renal events, especially in patients undergoing coronary angiography. In research and diagnostic settings, measurement of both serum and urinary VDBP levels can aid in assessing vitamin D status, monitoring inflammatory conditions, and evaluating renal function in at-risk patient populations.
This product is manufactured in USA by Eagle Biosciences.