ANTIPHASE SHIFTING OF CLOCK GENES EXPRESSION IN BROWN FAT TISSUE OF RATS SUBMITTED TO FOOD RESTRICTION

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 649-675-Central Regulation of Appetite & Feeding/GI Regulatory Peptides
Bench to Bedside
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-669
Jennyfer Fernanda Rodrigues Domingues*1, Leonardo Domingues Araújo2, Fernanda Borchers Coeli Lacchini3, Silvia Ruiz Roa4, Ernane Torres Uchoa5, Lucila Elias2, Jose Antunes-Rodrigues6, Ayrton Custodio Moreira7, Margaret De Castro7 and Paula CL Elias4
1School of Medicine of Ribeirão Preto - University of São Paulo, Ribeirao Preto, Brazil, 2School of Medicine of Ribeirao Preto of University of Sao Paulo, Ribeirao Preto, Brazil, 3School of Medicine of Ribeirão Preto - University of São Paulo, RIBEIRÃO PRETO, Brazil, 4School of Medicine of Ribeirao Preto- University of Sao Paulo, Ribeirao Preto SP, Brazil, 5University of Sao Paolo-FRMP, Ribeirao Preto-SP, Brazil, 6Univ of Sao Paulo Sch of Med, Ribeirao Preto SP, Brazil, 7School of Medicine of Ribeirao Preto-University of Sao Paulo, Ribeirao Preto-SP, Brazil
Introduction: Anticipating food access is associated to changes in gene expression involved in the biological clock system regulation. However, few studies have evaluated the expression of genes regarding food restriction patterns. Objectives: To evaluate the expression of clock genes in brown fat tissue in animals submitted to food restriction. Material and Methods: Wistar rats were submitted to different dietary patterns for 21 days. Control group (CG): food and water ad libitum, Food Restriction group (FR): food from 1800 to 2000h, and Food Shift (FS): food from 0900 to 1100h. Animals were decapitated at 0900 and 1700h. Blood was collected for corticosterone (B), measured by RIA. Brown fat tissue was harvested and flash frozen in liquid nitrogen. RNA was extracted by Trizol. Expressions of Clock, Bmal1, Per1-3 and Cry1-2 genes were determined by qPCR and expressed as 2-ΔΔCT. Results: CG animals showed greater weight compared to FR and FS groups (385.4±55.4g vs 245.5±32.0g vs 227.9±40.9g; P<0.0001). CG animals and FR group showed lower B levels (µg/dL) at 0900 vs 1700h (1.0±0.6 vs 14.1±8.1, P<0.001) and (3.6±2.6 vs 20.7±7.6, P<0.0001), respectively. FS group showed an inverted pattern of B secretion compared to CG animals with higher levels at 0900 vs 1700h (22.7±6.2 vs 10.6±5.7, P=0.0007). There was no difference in the expression of Clock gene inter- and intra-groups.  Bmal1 gene showed higher expression in CG at 0900 compared to 1700h (1.1±0.3 vs 0.2±0.1; P<0.05). An inverse pattern was seen in FS animals (1.1±0.6 vs 1.7±0.6; P<0.05). On the other hand, Per1, Per2 and Per3 genes showed lower expression in CG at 0900 compared to 1700h (1.0±0.5 vs 4.3±2.7; 1.0±0.8 vs 3.6±1.7 and 1.4±1.0 vs 3.5±1.9;  P<0.05), respectively. In FS animals a higher expression of Per1 and Per2 genes was observed at 0900h (1.6±1.2 vs 0.6±0.6; and 1.3±0.9 vs 0.6±0.6; P<0.05). Additionally, Cry1-2 genes were also less expressed at 0900 compared to 1700h in CG animal (0.9±0.2 vs 2.2±1.3; and 1.2±0.5 vs 2.1±1.1; P<0.05). Conclusion: In control animals our data corroborate the described antiphase circadian expression pattern between Bmal1 and Per1-3, Cry1-2 genes. Additionally, change in feeding time from night to day modulated the expression of Bmal1 and Per1-2, accompanied by inverted B levels, in the brown fat tissue which is related to non-photic signals and involved in energy homeostasis and food motivation.

Nothing to Disclose: JFRD, LDA, FBCL, SRR, ETU, LE, JA, ACM, MD, PCE

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: FAPESP Grant 07/58365-3