title: A circulating inhibitor of platelet aggregation in Bartter's syndrome.
abstract: Aggregation studies were performed on platelets from five patients with Bartter's syndrome. Epinephrine failed to induce aggregation in all five patients. Adenosine 5'-diphosphate (ADP) produced a single reversible phase of aggregation, and there was depressed sensitivity to collagen. Response to ristocetin was normal. There was a dose-related inhibition of ADP-induced platelet aggregation when plasma from the patients was addeded to normal platelet-rich plasma. This inhibition was diminished or absent when patients were receiving aspirin. Washed platelets from two patients who were no longer undergoing aspirin therapy, showed a normal response to epinephrine in normal platelet-poor plasma. Bleeding time was reduced from 23 minutes to 12 minutes in one patient while on aspirin therapy. These studies suggest that a circulating inhibitor of platelet aggregation, probably of prostaglandin origin, is present in the plasma  of patients with Bartter's syndrome.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D001241:Aspirin / Q000494:pharmacology / Q000627:therapeutic use; D001477:Bartter Syndrome / Q000097:blood* / Q000188:drug therapy; D001760:Bleeding Time; D003094:Collagen / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood*; D007223:Infant; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*
chemical_list: D016861:Cyclooxygenase Inhibitors; D000244:Adenosine Diphosphate; D003094:Collagen; D001241:Aspirin; D004837:Epinephrine