To investigate the impact of exogenous of triiodothyronine (T₃) on the liver hyperplasia of mouse.

Forty-five healthy specific pathogen free (SPF) C57BL/6 mice were divided into group A, B and control group using random number table method with 15 mice in each group. Mice in group A, B were respectively injected with 2 ml exogenous T₃ solutions 10, 5 μg/kg intraperitoneally. Mice in control group were injected with 2 ml normal saline. Three mice of each group were put to death respectively on day 0, 7, 14, 21, 42 after treatment. The total liver weight of the mice was measured after death. The proliferation of liver cells was detected by immunohistochemistry. The experimental data were compared using t test or analysis of variance.

Compared with control group, the liver weight of mice in group A increased significantly on day 7, 14, 21, 42 after treatment (t=3.298, 6.760, 7.119, 6.128; P<0.05) , and the liver weight of mice in group B increased significantly on day 14, 21, 42 after treatment (t=4.188, 4.570, 2.978; P<0.05). The increased liver weight in group A was significantly more than that in group B on day 7, 14, 21, 42 after treatment (t=4.935, 4.303, 4.033, 4.480; P<0.05). The liver weight in group A, B rose to the top on day 21 after treatment (F=21.480, 11.244; P<0.05). Compared with control group, the liver cell count in group A increased significantly on day 0, 7, 14, 21, 42 after treatment (t=28.383, 23.842, 40.194, 31.059, 15.841; P<0.05), and the same with group B (t=9.097, 7.680, 20.597, 42.192, 14.415; P<0.05). The increased liver cell count in group A was significantly more than that in group B (t=8.016, 4.872, 10.719, 9.514, 7.831; P<0.05). The liver cell count rose to the top in group A on day 14 after treatment (F=169.190, P<0.05) and rose to the top in group B on day 21 after treatment (F=90.460, P<0.05). Extensive proliferation of liver cells was observed both in group A and B after treatment.

Exogenous T₃ can effectively promotes the liver hyperplasia of mouse, and the hyperplasia becomes more significant as the T₃ concentration rises.