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.
Keeping in mind that not all obese have any form of leptin resistance, this study involved 8 obese and 23 lean individuals. It found that while serum leptin levels were 318% higher in the 8 obese individuals than the lean controls, the cerebrospinal fluid leptin levels were only 30% higher. How leptin is transported through the brain blood barrier appears to involve a receptor at the blood/cerebrospinal fluid barrier.