PhD defence: Lipolysis in Skeletal Muscle - Regulation and Insulin Sensitiviy

Annette Karen Lundbeck Serup

PhD thesis

Fat is stored in skeletal muscle as intramuscular triacylglycerol (IMTG). IMTG is utilized by lipolysis during situations with low cellular energy availability, such as exercise. The energy sensor AMPK is associated with regulation of lipolysis, however, whether AMPK is an activator or inhibitor of lipolysis in skeletal muscle is not clear. Results from this PhD thesis shows that AMPK is an important activator of lipolysis during muscle contractions by phosphorylating the lipases ATGL and HSL.

Dysregulation of lipolysis results in accumulation of DAG and DAG is associated with impaired insulin sensitivity in skeletal muscles, however not all studies can detect this association between DAG accumulation and impaired insulin sensitivity. DAG exists in different chemical structures depending on how it is generated, and has different reactivity. Thus, the role of DAG in impaired insulin sensitivity in skeletal muscle may be dependent on the chemical structure of DAG. Results from this PhD thesis shows that DAG accumulation originating from dysregulation of lipolysis is not an important signaling molecule in impaired insulin sensitivity in skeletal muscle.

2017, 189 pages.

Time

5 May 2017, 14:00

Place

Auditorium 1, August Krogh Building, Universitetsparken 13, DK-2100 Copenhagen.

Opponents

Associate professor Nikolai Nordsborg (chair), Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.

Professor Gregory R. Steinberg, McMaster University, Canada.

Co-director Cedric Moro, The Obesity Research Laboratory, INSERM, Frankring.

Supervisor

Professor Bente Kiens, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.