Pinealectomy alters Cry 1 and Rev‐erbα gene expression in epididymal adipose tissue (LB758)

Biological rhythms, besides being under melatonin control, are also controlled by genetic mechanisms, which inform to neuronal and peripheral structures about circadian rhythms. Circadian system are driven by a series of interacting clock genes resulting in 24 hour cycles of gene expression. Clock genes may interact with metabolic genes and regulate their transcription, promoting a proper homeostasis. Disturbances in the rhythm of these genes can promote overweight and increased abdominal fat deposition leading to obesity and metabolic syndrome. Thus, the present study aimed to investigate the circadian rhythm of gene expression of clock genes, and, metabolic genes in pinealectomized animals. One month after pinealectomy, pinealectomized (Pinx) and control (Ctl) animals were sacrificed in different zeitgeber times (Zts: 0,4,8,12,16,20,24). Epididymal fat pad was removed and processed for Pparγ, Bmal1, Clock, Cry1 and Rev‐erbα gene expression. These genes were analyzed by quantitative reverse‐transcriptase PCR. Daily curves for clock and metabolic genes were tested with Anova‐one way and Cosinor analysis. Results: a) Cry 1 circadian rhythm was lost in pinealectomized rats (p<0.05); b) Bmal 1 and Clock daily oscillation did not change in the absence of melatonin; c) the expression of Rev‐erbα increased in Pinx rats (p<0.05); e) Pparγ temporal pattern was lost in Pinx rats. Although it was not observed changes in body weight and in epididymal fat depots, it was found significant differences in the gene expression of clock genes Cry1 and Rev‐erbα. Also the Pparγ temporal pattern has been altered in Pinx animals. Since it is already known that changes in the expression of these clock genes are associated with obesity‐related traits, probably the long‐term changes in these genes could be crucial for the development of a disorder of energy metabolism. Grant Funding Source : Supported by Fapesp