Cancer Letters, zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 19 (1983) 247-252 Elsevier Scientific Publishers Ireland Ltd. 247 zyxwvutsrq SPONGIOSIS HEPATIS IN RATS TREATED WITH LOW DOSES OF HEPATOTROPIC NITROSAMINES HEIDE ZERBAN and PETER BANNASCH* Abteilung fiir Cytopathologie, Institut fiir Experimentelk Pathologie, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 6900 Heidelberg (F.R.G.) (Received 17 February 1983) (Accepted 21 March 1983) SUMMARY Spongiosis hepatis, a characteristic pathomorphologic entity originating from the perisinusoidal liver cells, was observed in rats after administration of relatively low doses of the hepatocarcinogens dimethylnitrosamine (DMNA) and nitrosopyrrolidine (NO-Pyr), but not after application of the urinary bladder carcinogen butyl-butanolnitrosamine (BBNA). The results support the conception that spongiosis is a persisting liver lesion due to specific changes of the perisinusoidal liver cells by hepatotropic carcino- gens. INTRODUCTION Spongiosis hepatis has been reported recently as a specific pathomorpho- logic entity in the liver of rats treated with N-nitrosomorpholine [ 21. Elec- tron microscopical investigations in this experimental model indicated that the lesion develops from the perisinusoidal liver cells which have been described as ‘fat storing cells’ by Ito and Nemoto [8] and investigated more closely during the past 3 decades [4]. Under the light microscope the areas of spongiosis appear as multilocular cyst-like complexes filled with a finely granular acidophilic material which, according to cytochemical findings, is usually rich in glycosaminoglycans and neutral mucopolysac- charides. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA We suggest that spongiosis hepatis might be due to a carcinogen- induced metabolic disorder of the perisinusoidal cells. This interpretation is supported by the present communication which deals with findings in different series of experimental animals treated with relatively low doses of DMNA, NO-Pyr or BBNA either alone or in combination with each *To whom all correspondence should be addressed. 0304-3835/83/$03.00 0 1983 Elsevier Scientific Publishers Ireland Ltd. Published and Printed in Ireland.