Figure 3. Redox homeostasis in TR/GR-null livers.
(a) Immunoblots for TrxR1 (top) or Trx1 (below). Hepatocytic genotypes at Gsr and Txnrd1 loci are indicated. M, molecular size markers (kDa). (b) NADPH-dependent GSSG-reductase activity. Hepatocytic genotypes at the Gsr and Txnrd1 loci are indicated;each dot represents one animal. (c) Hepatic levels of total glutathione (GSH + GSSG) and oxidized glutathione disulfide (GSSG) are shown. n = 4 animals each for wild-type and TR/GR-null livers (first and last bars), and 2–7 animals each for other genotypes; bars represent mean ± SEM. No differences in GSH + GSSG levels were significant, Student’s T-test. Mean GSSG values were, from left to right, 0.17, 0.09, 0.15, 0.32, and 0.12 nmol.mg−1 liver, respectively. (d) Total protein thiol content in wild-type and TR/GR-null livers. Acid-precipitated total liver proteins were resuspended in acidic denaturing buffer and reacted with 4,4’-dithiol pyridine. Comparison to a standard curve was used to quantify protein thiol (SH) content and this was normalized to total amino acid (a.a.) content. n = 9 wild-type and 8 TR/GR-null livers. (e) Proliferation rates in regenerating or resting livers. Mice were either 2/3 hepatectomized or not. As indicated, BSO was administered 32 h later and 2 h after that bromodeoxyuridine (BrdU) was administered. Livers were harvested 12 h later and BrdU-labeled (S phase) nuclei were enumerated. n = 3–5 for each condition; graphs show mean and SEM. *, P ≤ 0.05, Student’s T-test.