Fig. 1 Upper panel, Autoradiographs of LD or SD female Siberian hamster brain sections (20-μm coronal sections; 8 wk postweaning) after in situ hybridization to an antisense <sup>35</sup>S-labeled riboprobe to SOCS3 mRNA (insets in the upper panel depict hybridization to SCN and PVN). Shown are representative sections of animals from each photoperiod. Lower panel, Darkfield photomicrographs showing high resolution images of the respective hypothalamic regions (boxed regions in upper panel) in both photoperiods. CA 1–3, CA 1–3 region; PC, pyriform cortex; 3V, third ventricle. From: Photoperiodic Regulation of Leptin Sensitivity in the Siberian Hamster, Phodopus sungorus, Is Reflected in Arcuate Nucleus SOCS-3 (Suppressor of Cytokine Signaling) Gene Expression Endocrinology. 2004;145(3):1185-1193. doi:10.1210/en.2003-1382 Endocrinology | Copyright © 2004 by The Endocrine Society
Fig. 2 Body weight change during 8 wk postweaning (A), serum leptin concentrations (B), and SOCS3 gene expression (C) of juvenile female Siberian hamsters fed ad libitum or food deprived for 48 h (n = 6) in LD or SD (n = 6). The body weight change gains significance from wk 5 onward (P < 0.05). The gene expression values are expressed as percentages of values in LD-ADLIB hamsters (mean ± sem). *, P < 0.05. From: Photoperiodic Regulation of Leptin Sensitivity in the Siberian Hamster, Phodopus sungorus, Is Reflected in Arcuate Nucleus SOCS-3 (Suppressor of Cytokine Signaling) Gene Expression Endocrinology. 2004;145(3):1185-1193. doi:10.1210/en.2003-1382 Endocrinology | Copyright © 2004 by The Endocrine Society
Fig. 3 SOCS3 gene expression in the hypothalamic ARC of juvenile female Siberian hamsters held in either LD or SD for 4, 7, 14, or 21 d postweaning (n = 4–8) and an LD weaning control group. Values are expressed as percentages of values in hamsters at weaning (mean ± sem). *, P < 0.05. From: Photoperiodic Regulation of Leptin Sensitivity in the Siberian Hamster, Phodopus sungorus, Is Reflected in Arcuate Nucleus SOCS-3 (Suppressor of Cytokine Signaling) Gene Expression Endocrinology. 2004;145(3):1185-1193. doi:10.1210/en.2003-1382 Endocrinology | Copyright © 2004 by The Endocrine Society
Fig. 4 Juvenile female Siberian hamsters (n = 12) were fed ad libitum in LD (LD-ADLIB) or SD (SD-ADLIB) for either 6 or 12 wk or were held in LD with restricted food from d 0 postweaning onward to mimic SD body weight trajectory (LD-REST). Figures show body weight trajectories and serum leptin concentrations (nanograms per milliliter; mean ± sem) at 6 wk (A) or 12 wk (B) postweaning, correlation between body weight and pooled white adipose tissue weight (C; IWAT, RWAT, and RTWAT), correlation between pooled white adipose tissue weight (D; IWAT, RWAT, and RTWAT) and serum leptin (y = 0,0135x −5.9285; r<sup>2</sup> = 0.8236), and SOCS3 gene expression (expressed as a percentage of LD-ADLIB; mean ± sem) in the ARC after 6 wk (E) or 12 wk (F). *, P < 0.001. From: Photoperiodic Regulation of Leptin Sensitivity in the Siberian Hamster, Phodopus sungorus, Is Reflected in Arcuate Nucleus SOCS-3 (Suppressor of Cytokine Signaling) Gene Expression Endocrinology. 2004;145(3):1185-1193. doi:10.1210/en.2003-1382 Endocrinology | Copyright © 2004 by The Endocrine Society
Fig. 5 Time-dependent effect (A) of leptin injection on SOCS3 gene expression in the hypothalamic ARC of juvenile female hamsters held in LD or transferred to SD for 8 wk (n = 3) and typical autoradiographic images (B) 1 h after injection [recombinant mouse leptin was injected ip at different time points (15, 30, 60, and 120 min) before preparation of the brains]. Values are expressed as percentages of values in LD 15 min vehicle-treated animals (mean ± sem). C, SOCS3 gene expression in the ARC of adult male Siberian hamsters in LD and SD (n = 6) 1 h after leptin injection. Values are expressed as percentages of values in LD animals injected with vehicle (mean ± sem). *, P < 0.001. From: Photoperiodic Regulation of Leptin Sensitivity in the Siberian Hamster, Phodopus sungorus, Is Reflected in Arcuate Nucleus SOCS-3 (Suppressor of Cytokine Signaling) Gene Expression Endocrinology. 2004;145(3):1185-1193. doi:10.1210/en.2003-1382 Endocrinology | Copyright © 2004 by The Endocrine Society