Parenchymal injury and biliary obstruction in relation to photosensitization in sporidesmin-intoxicated lambs.

The hepatic changes were compared in lambs photosensitized or not photosensitized after exposure to sporidesmin. Injury to both the parenchyma and the biliary system was more severe in the photosensitized than in the non-photosensitized lambs. The activities of gamma-glutamyltransferase and glutamate dehydrogenase, and the total, conjugated and unconjugated bilirubin concentrations were significantly higher in sera from the photosensitized than from the non-photosensitized lambs. Hepatic glycogen levels were decreased in both the photosensitized and the non-photosensitized lambs, but were significantly lower in the former. Hence it is possible that lesions in hepatocytes contribute to retention of phylloerythrin and so to photosensitization.