Bilirubin accumulation by the rabbit choroid plexus in vitro.

The postnatal development of bilirubin accumulation by the choroid plexus was studied in vitro. Choroid plexus of the fourth and lateral cerebral ventricles from adult or 1-, 7-, 15- or 21-day-old rabbits were incubated in a potassium-rich medium with 70 nmol/l of 3H-bilirubin for 5 min. The tissue/medium (T/M) ratio for 3H-bilirubin was considerable even 1 day post partum and increased during the next 2–3 weeks of life. In adults the 3H-bilirubin T/M ratio returned to the level of 1-day-old rabbits. The biliary excreted contrast agent iodipamide, added as a transport inhibitor, reduced the 3H-bilirubin T/M ratio in the choroid plexus, but to a relatively lesser extent in the 1-day-old rabbits than in the older ones.