Levels and disappearance of prostaglandin F2alpha in cerebral spinal fluid: a clinical and experimental study.

The concentration of prostaglandin F2alpha (PGF2alpha) was measured in cerebrospinal fluid (CSF) obtained by lumbar puncture in patients with subarachnoid hemorrhage and compared to control values. The level of this prostaglandin was elevated at some time in most patients during the course of their illness. However, this could not be correlated with the severity of neurological deficits observed. The possibility that the concentration of PGF2alpha in lumbar fluid may not reflect that present intracranially was tested experimentally in anesthetized dogs. In these experiments only a small fraction of the radioactive PGF2alpha injected into the cisterna magna appeared in lumbar CSF. Prostaglandin F2alpha rapidly disappeared from the cisterna magna, half time 8 minutes, and radioactivity was present in blood from the jugular vein indicating that normally this prostaglandin rapidly egresses from the CSF into blood. These findings suggest that PGF2alpha can be rapidly transported away from the brain. This could explain the low concentrations of PGF2alpha in CSF of normal individuals and in some patients who have severe cerebral vasospasm. Conversely, the elevation of PGF2alpha in lumbar CSF noted in some patients might be due, in part, to an impairment of transport caused by the size and location of the hemorrhage.