Effect of sodium benzoate on the cutaneous bilirubin content of the adult Gunn rat.

Na benzoate, which dissociates intravascular bilirubin-albumin complexes, might thus have the potential for driving bilirubin from the plasma into tissues such as the skin. We investigated this hypothesis in the adult Gunn rat. As others, we observed an early fall in blood bilirubin concentration after intraperitoneal Na benzoate injection, without any change in skin bilirubin content. Nevertheless, we observed a significant decrease (p less than 0.01) in skin bilirubin content at 24 and then 48 h after Na benzoate injection, at which times blood bilirubin remained at a low level. The phenomenon was reversible since, at 8 days after Na benzoate injection, blood and skin bilirubin contents had returned to control values. Regarding the decrease in skin bilirubin content after Na benzoate injection we described a dose-effect relationship. So, we could not confirm our hypothesis. We concluded that the phenomenon we observed is probably due to a shift in the distribution equilibrium of the pigment between serum, skin and other tissues.