Comparative investigation of the effect of vasopressin and of its structural analogue DGAVP on aggregation of blood platelets

In experiments in vitro, the effects of vasopressin and of its analogue DGVAP on aggregation of platelets are compared. Addition of peptides causes aggregation both in plasma rich in platelets both in humans and rats. In the human plasma DGVAP is a much stronger inductor of aggregation than vasopressin, whereas in the plasma of rats the effects are identical. Vasopressin and DGVAP considerably increase thrombin-induced aggregation of washed platelets of rats but do not influence ADP-induced aggregation of platelets. Thus, multifunctional action of these peptides on aggregation of platelets may depend both on their direct interaction with platelets and on a potential synergic action of peptides with other agonists.