Fig. 4

Mitochondrial enzyme activity in the liver of tadpoles. Tadpoles (n = 8/group) were reared in dechlorinated tap water at 26 °C with or without 5 nM 3,3′,5-triiodothyronine (T3; 26C and 26T, respectively) or at 4 °C with or without 5 nM T3 (4C and 4T, respectively) for 3 days (A, C) or 7 days (B, D). A, B Cytochrome c oxidase (COX) activity and the membrane protein amount. C, D Carnitine palmitoyltransferase (CPT) activity and membrane protein amount. Each assay was carried out using mitochondria-rich fractions obtained from the livers of two animals. Values are mean ± SEM (n = 4). The activities are presented as either units per mg of membrane protein (U or mU/mg protein, blue) or units per g of liver (U or mU/g liver, red). Membrane protein amounts are presented as mg per g of liver [protein (mg)/liver (g), yellow]. Different letters indicate significantly different means among the four groups and were determined by one-way analysis of variance with Fisher’s test for multiple comparisons (p < 0.05). Significant difference between the enzyme activities (U or mU/g liver) and membrane protein amounts were detected on day 3 (A, p < 0.01; C, p < 0.05) but not on day 7 (B and D) by two-way analysis of variance with Fisher’s test for multiple comparisons. These experiments were repeated two times, with similar results