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Postprandial hormone and metabolic responses in simulated shift work
S M Hampton1, L M Morgan, N Lawrence
1School of Biological Sciences, University of Surrey, Guildford, UK.
The Journal of Endocrinology
|November 1, 1996
Summary
Simulated shift work significantly alters postprandial glucose and insulin levels, impacting lipid metabolism. This disruption affects pancreatic B-cell responses and delays the return of fatty acids to basal levels.
Area of Science:
- Metabolic Physiology
- Chronobiology
- Endocrinology
Background:
- Shift work is prevalent and associated with metabolic disturbances.
- Understanding the impact of circadian misalignment on postprandial metabolism is crucial.
Purpose of the Study:
- To investigate the effects of a simulated 9-hour phase advance on postprandial metabolic responses to a mixed meal.
- To assess changes in glucose, insulin, incretin hormones (GIP, GLP-1), triacylglycerol (TAG), and non-esterified fatty acids (NEFAs).
Main Methods:
- Nine healthy subjects consumed a test meal at the same clock time (13:30h) under normal and phase-shifted conditions.
- Blood samples were collected for 6 hours post-meal to measure plasma glucose, insulin, GIP, GLP-1, TAG, and NEFAs.
- Areas Under the Curve (AUC) were calculated for different time intervals to quantify responses.
Main Results:
- Phase-shifted conditions led to significantly higher postprandial glucose and insulin levels, particularly in the later 4 hours.
- No significant differences were observed in postprandial GIP and GLP-1 responses.
- Plasma TAG levels were delayed and continued to rise post-phase shift, while NEFA levels showed a delayed return to basal.
Conclusions:
- Simulated shift work significantly alters pancreatic B-cell function and postprandial glucose metabolism.
- Circadian misalignment induced by phase shifting negatively impacts lipid metabolism, delaying TAG clearance and NEFA re-esterification.
- These findings highlight the metabolic consequences of disrupted circadian rhythms.