The effect of unconjugated bilirubin on regional cerebellar energy metabolism.

Many previous studies have examined the effects of unconjugated bilirubin on cerebral energy metabolism. The results have been equivocal largely because the samples for assay included contiguous less affected tissue. The present study was undertaken to obviate this problem. Kernicteric Gunn rat cerebella were sectioned, freeze dried, and Purkinje cell rich layers prepared, as well as adjacent molecular and granular layers. These layers were assayed, along with suitable controls, for glucose, glucogen, ATP, and phosphocreatine. ATP and phosphocreatine were decreased in the Purkinje cell rich layer only; molecular and granular layers were unaffected. Glucose and glycogen were increased in all three layers. These results support the concept that in vivo, bilirubin exerts its toxic effect by uncoupling oxidative phosphorylation.