Induction of Hepatocellular Carcinomas in the Egyptian Toad <i>Bufo regularis</i> by an Antifungal Drug (Griseofulvin)

Abstract

Neoplastic lesions (hepatocellular carcinomas) were induced in the liver in 18 of 100 experimental toads (Bufo regularis) force fed with the antifungal drug griseofulvin, at a dose level of 0.4 mg/50 g every day. Maximal time of exposure and observation was 12 weeks. The first tumors appeared in 2 male toads 4 weeks after the initiation of feeding.

Ultrastructural Criteria That Prove the Similarities between Amphibian and Human Tumors

“…The models have in cluded Xenopus laevis [4][5][6], Rana pipiens [7,8] and Bufo regularis [9,10], Some investigators have shown that toads can be used as a model to study the development of carcinogens [11], cocarcinogens [12] and vitamins [13], In the majority of these studies, the diagnosis of the induced tumors was based essentially on light microscopy.…”