Decreased cerebrospinal-fluid/serum leptin ratio in obesity: a possible mechanism for leptin resistance

Authors: Caro, J.F., Kolaczynski, J.W., Nyce, M.R., Ohannesian, J.P., Opentanova, I., Goldman, W.H., Lynn, R.B., Zhang, P-L., Sinha, M.K., Considine, R.V.
"Our data suggest that leptin enters the brain by a saturable transport system. The capacity of leptin transport is lower in obese individuals, and may provide a mechanism for leptin resistance."