Transient Responses of the Hepatic Lipidome to Acute Exercise Bouts in Mice

Abstract

BACKGROUND: The content of triacylglycerol (TAG) in the liver is known to rapidly increase after a single bout of exercise followed by recovery to sedentary levels. The response of other hepatic lipids, and acyl chain composition of lipid classes, would provide a deeper understanding of the response of hepatic lipid metabolism to acute exercise. METHODS: Female mice performed a single bout of continuous exercise (CE), high-intensity interval exercise (HIIE), or no exercise (CON). The total content of various lipids in the liver, and fatty acids within lipid classes, were measured in tissues collected 3 hours after exercise (Day 1) and the day following exercise (Day 2). RESULTS: The total concentration of TAG rose on Day 1 after exercise (P < 0.05), with a greater elevation in HIIE than CE (P < 0.05), followed by a decline toward CON levels on Day 2. The total concentration of other measured lipid classes was not significantly altered by exercise. However, n-6 polyunsaturated fatty acid relative abundance in diacylglycerol (DAG) was increased by HIIE (P < 0.05). In CON liver, TAG content was positively correlated with DAG and phosphatidylethanolamine (P < 0.05), while these statistical associations were disrupted in exercised mice on Day 1. CONCLUSIONS: Overall, the results characterize flexibility of the hepatic TAG pool size in the liver, and the relationship between TAG and other lipid abundances is altered during the transient TAG pool expansion after exercise. The transient expansion of the hepatic TAG pool and remodeling of the DAG pool may be fundamental components of the physiological response to intense exercise.