Arginine vasotocin-like activity of cerebrospinal fluid in diabetes insipidus.

Cerebrospinal fluid (CSF) from patients with idiopathic diabetes insipidus (DI) contains an active principle with antidiuretic, hen oviduct and frog bladder activities. Tryptic digestion of the biological activities suggests that the active principle is a peptide containing at least one basic amino acid. The biological activities of CSF from DI patients differ significantly from those of arginine vasopressin (AVP) and oxytocin, but are not significantly different from those of arginine vasotocin (AVT). No such biological activities could be detected in the CSF of normal subjects of the same age and sex.