Zinc-transporter genes in human visceral and subcutaneous adipocytes: Lean versus obese

Zinc ions influence adipose tissue metabolism by regulating leptin secretion and by promoting free fatty acid release and glucose uptake. The mechanisms controlling zinc metabolism in adipose tissue are unknown. We therefore examined the gene-expression levels of a number of zinc-transporting proteins in adipose tissue, comparing subcutaneous fat with visceral fat from lean and obese humans. Both ZnT-proteins responsible for zinc transport from cytosol to extracellular compartments and intracellular vesicles and Zip-proteins responsible for zinc transport to the cytoplasm were expressed in all samples. This suggests that zinc metabolism in adipocytes is actively controlled by zinc-transporters. The expression levels were different in lean and obese subjects suggesting a role for these proteins in obesity. Furthermore, the expression levels were different from subcutaneous fat to intra-abdominal fat suggesting that the metabolic activity in adipocytes is to some extent dependent upon zinc and the activity of zinc-transporting proteins or vice versa.