Veno-occlusive lesions in the liver of rats after prolonged feeding with palmyrah (Borassus flabellifer) flour.

Flour from the young shoot of the palmyrah palm (Borassus flabellifer) which is consumed by people in certain tropical countries, when fed for prolonged periods to adult male rats produced chronic hepatic lesions which included intraluminal fibrosis of the centrilobular and portal veins, bile duct proliferation, increase of reticulin and fibrosis. Thromboses of the hepatic veins was not seen. The vascular lesions commenced as a subendothelial swelling which projected into the lumen and in which collagen deposition ended in almost total obliteration of the lumen. No hepatic megalocytosis was seen. It is suggested that the toxic factor(s) responsible are different from the pyrrolizidine alkaloids and dimethylnitrosamine which have been well documented to produce similar lesions.