Volume 6, Issue 1, Pages 79-87 (July 2007) Serum Retinol-Binding Protein Is More Highly Expressed in Visceral than in Subcutaneous Adipose Tissue and Is a Marker of Intra-abdominal Fat Mass  Nora Klöting, Timothy E. Graham, Janin Berndt, Susan Kralisch, Peter Kovacs, Christopher J. Wason, Mathias Fasshauer, Michael R. Schön, Michael Stumvoll, Matthias Blüher, Barbara B. Kahn  Cell Metabolism  Volume 6, Issue 1, Pages 79-87 (July 2007) DOI: 10.1016/j.cmet.2007.06.002 Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 1 Relationship between RBP4 mRNA in Adipose Tissue Depots and Serum RBP4 Concentrations, Adipose Tissue GLUT4 mRNA, and Adipocyte Size in Human Subjects (A–D) RBP4 mRNA levels in entire study population (n = 196), including lean, obese, nondiabetic, and diabetic subjects (A), males (n = 98) and females (n = 98) (B), normal glucose tolerance (NGT) subjects (n = 129) or impaired glucose tolerance (IGT) and type 2 diabetes (T2D) subjects grouped together (n = 67) (C), and subgroups of lean (n = 53), visceral obese (Vis, n = 21), and subcutaneous obese (SC, n = 55) subjects with NGT (D). (E and F) Correlations between serum RBP4 concentration and RBP4 mRNA expression in Vis adipose tissue (n = 163) (E) and SC adipose tissue (n = 163) (F). (G and H) Correlation between RBP4 mRNA and GLUT4 mRNA in Vis adipose tissue (n = 196) (G) and SC adipose tissue (n = 196) (H). (I) Correlation between adipocyte size and RBP4 mRNA in Vis (•) and SC (○) adipose tissue biopsies from lean, SC obese, and Vis obese subjects (n = 20 per group of mixed NGT, IGT, and T2D subjects). Data were log transformed to achieve a normal distribution. (E) and (F) include those subjects for whom measurements of all parameters were available (i.e., serum RBP4 was measured in 163 of the 196 subjects). Vis fat area and the relative ratio of Vis fat to SC fat area were calculated using CT scans at the level of L4–L5. Values are means ± SEM. ∗p < 0.01; ∗∗p < 0.001 for bracketed comparisons. #p < 0.01 for NGT versus IGT/T2D groups for the same fat depot in (C); ap < 0.01 for obese groups versus the lean group comparing the same fat depot in (D); bp < 0.01 for the Vis obese group versus SC obese group comparing the same fat depot in (D). Cell Metabolism 2007 6, 79-87DOI: (10.1016/j.cmet.2007.06.002) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 2 Serum RBP4 and Transthyretin Concentrations in Lean, Obese, and IGT/T2D Subjects (A) Serum RBP4 concentrations in healthy lean and obese subjects with NGT (n = 129) and subjects with IGT/T2D (n = 67). Horizontal lines in all panels represent means of the values. (B) Serum RBP4 concentrations in NGT subgroups: lean NGT (n = 53), Vis obese NGT (n = 21), and SC obese NGT (n = 55). In (B), (E), (F), and (H), to categorize obese subjects according to patterns of adipose tissue distribution, intra-abdominal (Vis) fat area (IAFA) and SC fat area were measured using CT scans at the level of L4–L5, and the relative ratio of Vis to SC fat area was calculated. (C and D) Relationship between serum RBP4 concentrations and % total body fat (C) or IAFA (D) in lean, obese, NGT, IGT, and T2D subjects (n = 163). In (C)–(F), data were log transformed to achieve a normal distribution. Data in (C)–(H) include only those subjects for whom all parameters were available. (E and F) Correlation between serum RBP4 concentration and fasting plasma insulin in Vis obese subjects (n = 29) (E) and SC obese subjects (n = 73) (F). (G) Serum transthyretin (TTR) concentrations in healthy lean and obese NGT subjects (n = 129) and subjects with IGT/T2D (n = 51). (H) Serum TTR concentrations in subgroups of lean (n = 53), Vis obese (n = 21), and SC obese (n = 55) subjects with NGT. ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p < 0.001 for bracketed comparisons. Cell Metabolism 2007 6, 79-87DOI: (10.1016/j.cmet.2007.06.002) Copyright © 2007 Elsevier Inc. Terms and Conditions