Concentrations of glucose, insulin and albumin in human paired CSF/serum samples.

<p>A: Correlation of CSF glucose with plasma glucose concentrations in humans (<i>P</i><0.0001, <i>r</i> = 0.49). B: Correlation of CSF insulin with serum insulin concentrations in humans (<i>P</i><0.0001, <i>r</i> = 0.40). C: Increased CSF/serum ration for albumin as marker for the blood-CSF barrier in older people and strong positive correlation with age (<i>P</i><0.0001, <i>r</i> = 0.42). D: CSF/serum ratio for insulin in older people and negative correlation with age in humans (<i>P</i> = 0.04, <i>r</i> = -0.16).