Sam Trammell

Sam Trammell

Assistant professor

The Grevengoed group is interested in a novel class of lipids known as n-acyl taurines (NATs). As a conjugate of a fatty acid and taurine, these amphiphilic lipids are excellent, endogenously produced detergents. Dr. Grevengoed has previously revealed a role of these metabolites in cell signaling through GPR119 and in fat absorption. Through my experience in metabolomics, I aided in her studies of the kinetics of NAT metabolism and revealed that NATs are a biliary lipid class whose concentration increases with dietary fish oil to comparable levels of bile acids. While continuing to improve NAT analytical methods, we are uncovering how NATs are synthesized, localized to bile and how NATs cause fat malabsorption.

In parallel with my work on n-acyl taurine biology, I am interested in appetite regulation. Fibroblast growth factor 21 (FGF21) is a macronutrient responsive hepatokine known to regulate lipid metabolism and macronutrient preference. Circulating FGF21 increases in response to carbohydrates, protein restriction and alcohol ingestion. In converse, high protein diets blunt FGF21 in the presence of its secretagogues. How these macronutrient signals integrate to regulate hepatic FGF21 remains poorly understood. Using mass spectrometry based metabolomics, I am uncovering a relationship between small molecule metabolites and FGF21.

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