Effects of acute and chronic STZ-induced diabetes on clock gene expression and feeding in the gastrointestinal tract.

Diabetes may shift clock gene expression within peripheral organs. However, little is known about the effect of diabetes on the gastrointestinal molecular clock. We therefore investigated the effect of diabetes on gastrointestinal clock gene expression.

Rhythmic changes in colonic motility are regulated by period genes.

Human bowel movements usually occur during the day and seldom during the night, suggesting a role for a biological clock in the regulation of colonic motility. Research has unveiled molecular and physiological mechanisms for biological clock function in the brain; less is known about peripheral rhythmicity. This study aimed to determine whether clock genes such as period 1 (per1) and period2 (per2) modulate rhythmic changes in colonic motility.

Transcriptional profiling of mRNA expression in the mouse distal colon.

Background & Aims: Intestinal epithelial cells and the myenteric plexus of the mouse gastrointestinal tract contain a circadian clock-based intrinsic time-keeping system. Because disruption of the biological clock has been associated with increased susceptibility to colon cancer and gastrointestinal symptoms, we aimed to identify rhythmically expressed genes in the mouse distal colon.

Methods: Microarray analysis was used to identify genes that were rhythmically expressed over a 24-hour light/dark cycle.

Clock gene expression in the murine gastrointestinal tract: endogenous rhythmicity and effects of a feeding regimen.

Background & Aims: Based on observations that the gastrointestinal tract is subject to various 24-hour rhythmic processes, it is conceivable that some of these rhythms are under circadian clock gene control. We hypothesized that clock genes are present in the gastrointestinal tract and that they are part of a functional molecular clock that coordinates rhythmic physiologic functions.

Methods: The effects of timed feeding and vagotomy on temporal clock gene expression (clock, bmal1, per1-3, cry1-2) in the gastrointestinal tract and suprachiasmatic nucleus (bmal, per2) of C57BL/6J mice were examined using real-time polymerase chain reaction and Western blotting (BMAL, PER2).