Homogeneous distribution of prolactin in human cerebrospinal fluid

Concentrations of prolactin were assayed from human cerebrospinal fluid (CSF). Samples were taken from lumbar CSF space (n=105 neurological patients) and from lateral ventricles (n=31 neurosurgical patients). Ventricular CSF samples were taken from operatively treated subarachnoidal hemorrhage (SAH) patients during the monitoring of intraventricular pressure. More voluminous and frequent sampling was obtained from six patients undergoing diagnostic pneumoencephalography (PEG) procedure. Prolactin concentrations in lumbar CSF ranged between undetectable and 2.8 ng/ml with a mean value of 0.78±0.54 (SD) ng/ml. Some fluctuation was seen in the fractionated samples taken at PEG, but no definitive gradient was noticed. Ventricular CSF concentrations of prolactin (n=18) were 0.85±0.67 (SD) ng/ml at operation (range : undetectable ? 2.5 ng/ml). Somewhat lower values were recorded in the 3-day postoperative period, prolactin mean concentrations being 0.3 ? 0.6 ng/ml. The CSF prolactin concentrations in the lateral ventricles and lumbar sac are practically identical with no concentration gradient between these compartments.