THE HYPOTHALAMIC AND ATRIAL CORONARY-DILATORY HORMONES IN THE MECHANISMS OF BLOOD COAGULATION

摘要

The effects of atiial polypeptide (AP) and neurohormone C (NHC) upon the interaction of human factor Xa (FXa) and human antithrombin III (ATIII) were followed by SDS-PAGE. Upon pre-incubation of FXa, ATTTI, or mixtures thereof with AP, there was a shift from total FXaa-ATTfl to FXap-ATTTI complexes and increases in both ATIIIM and FXay. FXay is produced upon degradation of the 1° and 2° complex to the 3° complex. AP appears to promote FXa-ATIII complex formation when pre-incubated with ATIII, or when added nearly simultaneously to FXa/ATHI mixtures. However, when AP is pre-incubated with FXa, the results are more consistent with inhibition of complex formation. NHC, in striking contrast to AP, displayed no net stimulation of transformation of the alpha to the beta form of complexes in any pre-mixture incubation. There was an increase in total complex formation, a decrease in ATIIIM, a decrease in FXay and little change in the ratio of free FXaa to FXap, or the ratio of FXaoc-ATHI to FXafJ-ATIII complexes. Therefore, NHC may act to suppress hydrolysis or proteolytic actions of FXa on the FXa-ATTH complexes, or autolytic activity of FXa, to the level of FXay via an as yet unknown mechanism. Additionally, NHC retards the hydrolysis of the FXa-ATIII complexes which form free FXa and ATHIM. A pharmacological role for PNC in the molecular mechanisms of blood clothing has thus been proposed.