Journal of Veterinary and Animal Sciences

Abstract

The object of this study was to assess the tumour promoting potential of Phenobarbital (PB) after initiation with N-Nitrosomethylurea (NMU). In the NMU group, hepatocytes showed mild toxic changes. The kidney manifested degenerative changes. There were squamous cell hyperplastic changes in the stomach. In the NMU + PB group, the liver showed toxic changes like vacuolation, granularity and necrosis of hepatocytes as well as preneoplastic changes like clear cell foci and focal hepatocellular dysplasia. Ultrastructurally the nuclei of hepatic cells showed an increase in interchromation granules. Besides, numerous vacuoles were also seen in the cytoplasm which could be due to dilatation and vesiculation of RER and SER due to ingress of water. The other changes included hyperaemia and tubular degeneration in the kidney, perivascular collection of mononuclear cells in the lungs, mild gliosis with focal proliferation of meningeal cells in the brain. In the testes, there were necrosis of spermatids and accumulation of debris in the seminiferous tubules. Mammary gland showed adenoma tous hyperplasia. The changes in the urinary bladder mucosa varied from marked epithelial proliferation to papillomatous foldings