Diurnal changes in vasopressin and oxytocin levels in cerebrospinal fluid of post-operative patients with intracranial aneurysms.

Diurnal changes in vasopressin and oxytocin levels in cerebrospinal fluid were investigated under normal diurnal conditions. The patients examined had ruptured intracranial aneurysms, and underwent neck-clipping operations and continuous drainage from the basal cistern. All of the patients recovered consciousness without signs of neurological deficit. The investigations were conducted for 2 days starting 5-9 days after the neck-clipping operations were performed. The oxytocin concentration decreased as night fell, remained low during this period and then increased during the day. The vasopressin level demonstrated no definite rhythmic tendency. No correlation was revealed between the changes in the concentrations of either vasopressin or oxytocin in the cerebrospinal fluid and the osmolality.