Albumin

Albumin is a blood plasma protein that is produced in the liver and forms a large proportion of all plasma protein.

The normal range of albumin concentrations in human blood is 3.5 to 5.0 g/dL, and albumin normally constitutes about 60% of plasma protein; all other proteins present in blood plasma are referred to collectively as globulin[?]. Albumin is essential for maintaining the oncotic pressure needed for proper distribution of body fluids[?] between intravascular compartments and body tissues.

Because smaller animals, (for example rats,) function at a lower blood pressure, they need less oncotic pressure to balance this, and thus need less albumin to maintain proper fluid distribution.

Functions of albumin:

• Maintains oncotic pressure
• Transports thyroid hormones
• Transports other hormones, particularly fat soluble ones
• Transports unconjugated bilirubin
• Transports many drugs
• Competitively binds calcium ions (Ca++)
• Buffers pH

Causes of albumin deficiency:

• Cirrhosis of the liver (most commonly).
• Decreased production (e.g. starvation).
• Excess excretion by the kidneys (such as in nephrotic syndrome[?]).
• Excess loss in bowel (protein losing enteropathy).