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VMH lesions downregulate the expression of Per2 gene in the pancreas in the rat
Takayoshi Kiba1, Yuri Kintaka, Yoko Suzuki
1Faculty of Health Care, Kiryu University, 606-7 Azami, Kasakake, Midori, Gunma, 379-2392, Japan.
Abstract:
The mammalian circadian system contains both central and peripheral oscillators. It was reported that the rhythmic expressions of period homolog 2 (per2) mRNA in peripheral tissues were abolished by the suprachiasmatic nucleus (SCN) lesions. However, there are no reports that ventromedial hypothalamic (VMH) lesions can directly affect the expression of clock genes in pancreas and liver. In the present study, we examined whether VMH lesions can affect the expression of the clock gene, per2 in these organs. Total RNA was extracted from rat pancreas and liver tissues, and differences in the gene expression profiles between rats at day 3 after VMH lesioning and sham-VMH-lesioned rats were investigated using DNA microarray and real-time quantitative analysis. These results showed that VMH lesions downregulated the expression of the clock gene, per2 in the pancreas, but not the liver in the morning. There is a possibility that VMH lesions may affect the expression of the clock gene, per2 in the pancreas.
Insights
Ventromedial hypothalamic (VMH) lesions in rats downregulated the expression of the period homolog 2 (per2) clock gene in the pancreas. This suggests VMH lesions may impact pancreatic circadian gene expression.
Area of Science:
- Chronobiology
- Neuroendocrinology
- Molecular Biology
Background:
- Mammalian circadian rhythms are regulated by central and peripheral oscillators.
- Suprachiasmatic nucleus (SCN) lesions abolish peripheral period homolog 2 (per2) mRNA rhythms.
- The direct impact of ventromedial hypothalamic (VMH) lesions on clock gene expression in peripheral organs remains uninvestigated.
Purpose of the Study:
- To investigate whether VMH lesions affect the expression of the clock gene, per2, in the pancreas and liver.
- To elucidate the role of the VMH in regulating peripheral circadian gene expression.
Main Methods:
- VMH lesioning and sham operations were performed on rats.
- Total RNA was extracted from pancreas and liver tissues on day 3 post-lesioning.
- Gene expression profiles were analyzed using DNA microarray and real-time quantitative PCR.
Main Results:
- VMH lesions significantly downregulated the expression of the per2 clock gene in the pancreas.
- No significant effect of VMH lesions on per2 gene expression was observed in the liver.
- The observed downregulation of per2 in the pancreas occurred in the morning.
Conclusions:
- VMH lesions can directly affect the expression of the per2 clock gene in the rat pancreas.
- The VMH plays a role in regulating circadian gene expression in peripheral organs like the pancreas.
- Further research is warranted to explore the mechanisms underlying VMH-mediated regulation of pancreatic per2 expression.
