scholarly journals Photoperiodic Regulation of Hypothalamic Retinoid Signaling: Association of Retinoid X Receptor γ with Body Weight

Endocrinology ◽  
2004 ◽  
Vol 145 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Alexander W. Ross ◽  
Catriona A. Webster ◽  
Julian G. Mercer ◽  
Kim M. Moar ◽  
Francis J. Ebling ◽  
...  

Abstract This study reports novel events related to photoperiodic programming of the neuroendocrine hypothalamus. To investigate photoperiod-responsive genes, Siberian hamsters were maintained in long or short photoperiods that generate physiological states of obesity or leanness. Microarray expression analysis first identified CRBP1 as a photoperiod-responsive gene, and then further studies using in situ hybridization and immunocytochemistry revealed that expression levels of several related retinoid-signaling genes were modulated in response to photoperiod changes. Genes of the retinoid-signaling pathway, encoding nuclear receptors (RXR/RAR) and retinoid binding proteins (CRBP1 and CRABP2) are photoperiodically regulated in the dorsal tuberomamillary nucleus (DTM): Their expression is significantly lower in short photoperiods and parallels body weight decreases. Studies in pinealectomized hamsters confirm that the pineal melatonin rhythm is necessary for these seasonal changes, and studies in testosterone-treated hamsters reveal that these changes in gene expression are not the secondary consequence of photoperiod-induced changes in steroid levels. Comparative studies using Syrian hamsters, which show divergent seasonal body weight responses to Siberian hamsters when exposed to short photoperiods, showed a distinct pattern of changes in retinoid gene expression in the DTM in response to a change in photoperiod. We infer that the DTM may be an important integrating center for photoperiodic control of seasonal physiology and suggest that the changes in retinoid X receptor γ expression may be associated with seasonal changes in body weight and energy metabolism.

1989 ◽  
Vol 257 (6) ◽  
pp. R1533-R1540 ◽  
Author(s):  
T. J. Bartness ◽  
J. M. Hamilton ◽  
G. N. Wade ◽  
B. D. Goldman

Siberian hamsters exhibit decreased body weight and fat after initial exposure to short photoperiods and increased body weight and fat after extended short photoperiod exposure. The purpose of the present experiments was to determine if uniform changes in white adipose tissue (WAT) pad weights and lipid metabolism correspond to these short photoperiod-induced changes in body fat. Carcass lipid content and testes and fat pad weights [retroperitoneal WAT (RWAT), epididymal WAT (EWAT), and inguinal and dorsal subcutaneous WAT, respectively] were decreased in male hamsters relative to their long day counterparts after 6 and 12 wk of short-day exposure. Moreover, EWAT and RWAT weight, EWAT specific lipoprotein lipase activity, and specific and total lipogenesis were disproportionately decreased relative to the subcutaneous fat pads. The changes in fat pad weight and metabolism were generally reversed coincident with the return to a long-day-like reproductive status after prolonged short-day exposure (24 and 30 wk). In a less detailed experiment, female Siberian hamsters had decreased body, fat pad, and uterine weights after 6 wk of short-day exposure; however, no fat pad-specific changes in weight were observed. The results of these experiments demonstrate that short-day-exposed male Siberian hamsters may be a useful model for examining mechanisms underlying fat pad-specific responses. In addition, gender appears to influence the pattern of short-day-induced lipid depletion in this species.


2005 ◽  
Vol 288 (6) ◽  
pp. R1800-R1805 ◽  
Author(s):  
Maiko Kawaguchi ◽  
Karen A. Scott ◽  
Timothy H. Moran ◽  
Sheng Bi

Running wheel access and resulting voluntary exercise alter food intake and reduce body weight. The neural mechanisms underlying these effects are unclear. In this study, we first assessed the effects of 7 days of running wheel access on food intake, body weight, and hypothalamic gene expression. We demonstrate that running wheel access significantly decreases food intake and body weight and results in a significant elevation of CRF mRNA expression in the dorsomedial hypothalamus (DMH) but not the paraventricular nucleus. Seven-day running wheel access also results in elevated arcuate nucleus and DMH neuropeptide Y gene expression. To assess a potential role for elevated DMH CRF activity in the activity-induced changes in food intake and body weight, we compared changes in food intake, body weight, and hypothalamic gene expression in rats receiving intracerebroventricular (ICV) CRF antagonist α-helical CRF or vehicle with or without access to running wheels. During a 4-day period of running wheel access, we found that exercise-induced reductions of food intake and body weight were significantly attenuated by ICV injection of the CRF antagonist. The effect on food intake was specific to a blockade of activity-induced changes in meal size. Central CRF antagonist injection further increased DMH CRF mRNA expression in exercised rats. Together, these data suggest that DMH CRF play a critical role in the anorexia resulting from increased voluntary exercise.


Endocrinology ◽  
2001 ◽  
Vol 142 (10) ◽  
pp. 4173-4181 ◽  
Author(s):  
Julian G. Mercer ◽  
Kim M. Moar ◽  
Tracy J. Logie ◽  
Patricia A. Findlay ◽  
Clare L. Adam ◽  
...  

2011 ◽  
Vol 49 (05) ◽  
Author(s):  
É Polyák ◽  
K Gombos ◽  
A Gubicskóné Kisbenedek ◽  
S Szekeresné Szabó ◽  
K Bonyárné Müller ◽  
...  
Keyword(s):  

2013 ◽  
Author(s):  
Husna Zulkipli ◽  
Norita Salim ◽  
Gabriele Anisah Froemming ◽  
Aletza Mohd Ismail ◽  
Hapizah Nawawi

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 464 ◽  
Author(s):  
Bright Asare-Bediako ◽  
Sunil Noothi ◽  
Sergio Li Calzi ◽  
Baskaran Athmanathan ◽  
Cristiano Vieira ◽  
...  

We sought to delineate the retinal features associated with the high-fat diet (HFD) mouse, a widely used model of obesity. C57BL/6 mice were fed either a high-fat (60% fat; HFD) or low-fat (10% fat; LFD) diet for up to 12 months. The effect of HFD on body weight and insulin resistance were measured. The retina was assessed by electroretinogram (ERG), fundus photography, permeability studies, and trypsin digests for enumeration of acellular capillaries. The HFD cohort experienced hypercholesterolemia when compared to the LFD cohort, but not hyperglycemia. HFD mice developed a higher body weight (60.33 g vs. 30.17g, p < 0.0001) as well as a reduced insulin sensitivity index (9.418 vs. 62.01, p = 0.0002) compared to LFD controls. At 6 months, retinal functional testing demonstrated a reduction in a-wave and b-wave amplitudes. At 12 months, mice on HFD showed evidence of increased retinal nerve infarcts and vascular leakage, reduced vascular density, but no increase in number of acellular capillaries compared to LFD mice. In conclusion, the HFD mouse is a useful model for examining the effect of prediabetes and hypercholesterolemia on the retina. The HFD-induced changes appear to occur slower than those observed in type 2 diabetes (T2D) models but are consistent with other retinopathy models, showing neural damage prior to vascular changes.


2000 ◽  
Vol 41 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Karin A. J.M. van der Lee ◽  
Michaël M. Vork ◽  
Johan E. De Vries ◽  
Peter H.M. Willemsen ◽  
Jan F.C. Glatz ◽  
...  

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2195
Author(s):  
Ester Arévalo Sureda ◽  
Xuemei Zhao ◽  
Valeria Artuso-Ponte ◽  
Sophie-Charlotte Wall ◽  
Bing Li ◽  
...  

Isoquinoline alkaloids (IQ) exert beneficial antimicrobial and anti-inflammatory effects in livestock. Therefore, we hypothesized that supplementing sows’ diets with IQ during gestation would decrease farrowing stress, affecting the piglets’ development and performance. Sows were divided into: IQ1, supplemented with IQ from gestation day 80 (G80) to weaning; IQ2, supplemented from gestation day 110 (G110) to weaning, and a non-supplemented (NC) group. Sow body weight (BW), feed intake, back-fat thickness and back-muscle thickness were monitored. Cortisol, glucose and insulin were measured in sows’ blood collected 5 d before, during, and after 7 d farrowing. Protein, fat, IgA and IgG were analyzed in the colostrum and milk. Piglets were monitored for weight and diarrhea score, and for ileum histology and gene expression 5 d post-weaning. IQ-supplemented sows lost less BW during lactation. Glucose and insulin levels were lower in the IQ groups compared to NC-sows 5 d before farrowing and had higher levels of protein and IgG in their colostrum. No other differences were observed in sows, nor in the measured parameters in piglets. In conclusion, IQ supplementation affected sows’ metabolism, reducing body weight loss during lactation. Providing IQ to sows from their entrance into the maternity barn might be sufficient to induce these effects. IQ improved colostrum quality, increasing the protein and IgG content, improving passive immunity for piglets.


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