Night-time feeding of Bmal1−/− mice restores SCFA rhythms and their effect on ghrelin

Feb 12, 2020The Journal of endocrinology

Night-time feeding restores daily gut acid rhythms and their influence on hunger hormone in mice lacking Bmal1

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Diurnal rhythms in caecal short-chain fatty acids (SCFAs) were observed to fluctuate in phase with feeding time.

Rhythmic changes in caecal and plasma SCFA levels were abolished in mice lacking the core clock gene Bmal1.
Feeding time restored fluctuations in caecal SCFA concentrations in Bmal1-/- mice.
Plasma SCFA concentrations did not affect gastric release of the hunger hormone ghrelin.
Inhibition of colonic ghrelin release by caecal SCFAs was rhythmic, occurring at specific times of the day.
The inhibitory effect of SCFAs on colonic ghrelin release was lost in Bmal1-/- mice but restored in those with restricted feeding.

AI simplified

The known crosstalk between short-chain fatty acids (SCFAs) and the circadian clock is tightly intertwined with feeding time. We aimed to investigate the role of the core clock gene Bmal1 and feeding time in the diurnal rhythms in plasma and caecal SCFA levels and in their effect on the release of the hunger hormone ghrelin in the stomach and colon. WT, Bmal1-/- (ad libitum fed) and night-time-restricted-fed (RF)-Bmal1-/- littermates were killed at zeitgeber time (ZT) 4 and 16. SCFA concentrations were measured by gas chromatography. To investigate the effect of SCFAs on ghrelin release, stomach and colonic full-thickness strips were incubated with Krebs or a SCFA mix mimicking plasma or caecal concentrations, after which octanoyl ghrelin release was measured by RIA. Diurnal rhythms in caecal and plasma SCFAs oscillated in phase but rhythmic changes were abolished in Bmal1-/- mice. RF of Bmal1-/- mice restored fluctuations in caecal SCFAs. Plasma SCFA concentrations failed to affect gastric ghrelin release. The effect of caecal SCFA concentrations on colonic ghrelin release was rhythmic (inhibition at ZT 4, no effect at ZT 16). In Bmal1-/- mice, the inhibitory effect of SCFAs at ZT 4 was abolished. RF Bmal1-/- mice restored the inhibitory effect and increased colonic Clock expression. To conclude, diurnal fluctuations in caecal SCFAs and the effect of SCFAs on colonic ghrelin release are regulated by feeding time, independent of the core clock gene Bmal1. However, local entrainment of other clock genes might contribute to the observed effects.

Full Text

Full text is available at the source.

View full text (HTML) ↗View full text ↗

Night-time feeding of Bmal1−/− mice restores SCFA rhythms and their effect on ghrelin

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief