Effect of thiouracil on liver enlargement in tumor-bearing rats

¹ Biomedical Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma

It is well known that the liver of animals bearing the Walker carcinosarcoma 256 enlarges during tumor growth. The effect of thiouracil administration and thyroidectomy on this hypertrophy was studied. Thiouracil administration prevented the usual liver enlargement in animals bearing the Walker tumor as well as the enlargement produced by toxohormone prepared from this tumor. Thyroidectomy also prevented an increase in liver mass in tumor-bearing animals. The effect of thiouracil on liver enlargement in tumor-bearing rats could be largely overcome by thyroxine supplementation. Liver regeneration was strikingly inhibited in partially hepatectomized tumor-bearing rats treated with thiouracil. A significant inhibition of regeneration was also noted in control animals receiving thiouracil.