Blue light and bilirubin excretion

Science  11 Apr 1980:
Vol. 208, Issue 4440, pp. 145-151
DOI: 10.1126/science.7361112


Blue light converts bilirubin in the skin of jaundiced rats to metastable geometric isomers that are transported in blood and excreted in bile. The same reaction probably occurs in jaundiced babies exposed to light, particularly during treatment with phototherapy. Excretion of unisomerized bilirubin is prevented by intramolecular hydrogen bonding, and the pigment has to be metabolized to more polar derivatives to be excreted efficiently.