Bilirubin is synthesized (mostly) in the spleen by phagocytic cells metabolizing hemoglobin from old RBCs.
Splenic vein feeds the unconjugated bilirubin
into the portal vein, where ~20% is taken up by hepatocytes per pass
in the blood is only found bc of small, normal reflux from hepatocytes.
- Nl ranges
- -Total bilirubin is <1.2mg/dL
- -direct (conjugated) is <0.2mg/dL
- -indirect (unconjugated) is the difference
-Most bile acid is recycled from the intestine (via sodium-coupled bile acid transporter in the ileum); only 10% is from new synthesis