VMH lesions downregulate the expression of Per2 gene in the pancreas in the rat

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.