We previously reported that glutamine was a major source of carbon for de novo fatty acid
synthesis in a brown adipocyte cell line. The pathway for fatty acid synthesis from glutamine
may follow either of two distinct pathways after it enters the citric acid cycle. The
glutaminolysis pathway follows the citric acid cycle, whereas the reductive carboxylation
pathway travels in reverse of the citric acid cycle from α-ketoglutarate to citrate. To quantify
fluxes in these pathways we incubated brown adipocyte cells in [U-13 C] glutamine or [5-13 …