What is the physiology of albumin distribution in the human body?

Updated: Sep 11, 2020
  • Author: Ruben Peralta, MD, FACS; Chief Editor: Michael R Pinsky, MD, CM, Dr(HC), FCCP, FAPS, MCCM  more...
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Answer

Tracer studies with iodinated albumin show that intravascular albumin is distributed into the extravascular spaces of all tissues, with the majority being distributed in the skin. Approximately 30-40% (210 g) of albumin in the body is found within the vascular compartments of the muscle, skin, liver, gut, and other tissues.

Albumin enters the intravascular space via 2 pathways. First, albumin enters this space by entering the hepatic lymphatic system and moving into the thoracic duct. Second, albumin passes directly from hepatocytes into the sinusoids after traversing the Space of Disse.

After 2 hours, 90% of secreted albumin remains within the intravascular space. The half-life of intravascular albumin is 16 hours. Daily losses of albumin from the intravascular space are approximately 10%. Certain pathological conditions, such as nephrosis, ascites, lymphedema, intestinal lymphangiectasia, and edema, can increase the daily loss of albumin from the plasma.

Albumin distributes into the hepatic interstitial volume, and the concentration of colloids in this small volume is believed to be an osmotic regulator for albumin synthesis. This is the principal regulator of albumin synthesis during normal periods without stress.


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