Expression of the energy substrate transporters in uterine fibroids.

Proliferating cells exhibit accelerated rates of substrate utilization, favoring glucose over fatty acids (FA's) oxidation. Protein-mediated transport is thought to play a predominant role in facilitating either glucose or FA routing into the cells. In the present study, we examined the expression of glucose transporters (GLUT-1, GLUT-4) and fatty acids transporters (FAT/CD36, FATP-1, FATP-4) at transcript and protein levels as well as cytosolic fatty acid binding proteins (H-FABP, ACBP) in human fibroids (n=74, size up to 3cm diameter) and compared with pair-matched healthy myometrium. Additionally lipid content (diacylglycerols, triacylglycerols and ceramide) was estimated by gas liquid chromatography (GLC). Uterine fibroids displayed decreased expression of both FAT/CD36 and FATP-1 proteins along with lower diacylglycerol (DAG) and triacylglycerol (TAG) content as compared to healthy pair-matched myometrium. The expression of glucose transport proteins (GLUT-4 and GLUT-1) remained relatively constant, although the higher expression of GLUT-1 in uterine fibroids did not reach the minimum significance threshold (p=0.056). However, no change in either cytochrome c oxidase (COX IV) or hydroxyacyl-CoA dehydrogenase (HADHSC) was observed and these data confirm a possible metabolic shift favoring glucose utilization over fatty acid oxidation in human uterine fibroids.