Differential effects of various stimuli on AVP levels in blood and cerebrospinal fluid.

Water deprivation, drinking water containing 2% NaCl, or systemic injection with histamine or nicotine markedly increased plasma levels of vasopressin in rats. In contrast, none of the applied stimuli changed vasopressin levels in the CSF collected simultaneously from the same animal. These data suggest that the blood levels of vasopressin are controlled quite differently from CSF levels of this hormone.