Induction of neoplasms in the Egyptian toad Bufo regularis by gibberellin A3.

Force feeding the Egyptian toads (Bufo regularis) with gibberellin A3 (10 ppm) twice a week for 5 months induced neoplasms in 8 out of 50 (16%) experimental animals. Primary tumours developed in the liver (hepatocellular carcinomas). Two secondary tumours in the kidneys and another 2 in the ovaries of toads developed due to metastases from the hepatocellular carcinomas. The results show that gibberellic acid (gibberellin A3) has a carcinogenic effect in the Egyptian toads.