Release of beta-lysin from platelets by thrombin and by a factor produced in heparinized blood.
Removal of calcium by either citrate, oxalate, or ethylenediaminetetraacetate inhibited coagulation of blood at an early stage and prevented the release of beta-lysin from platelets. In contrast, heparin caused platelet agglutination and stimulated beta-lysin release in vitro and in vivo. This release was calcium dependent and may have been due to a calcium-dependent reaction in the blood coagulation sequence. Thrombin which by-passed the early calcium-dependent stages of coagulation directly stimulated the release of beta-lysin from platelets. However, thrombin alone or in combination with other plasma factors was not as effective in releasing beta-lysin as the regular coagulation process. Thrombin's platelet degranulating activity correlated with its beta-lysin releasing activity. In contrast to thrombin, staphylococcal coagulase, which also by-passed the calcium-dependent stages of coagulation, coagulated citrated blood without releasing beta-lysin. The release of beta-lysin has been observed previously in the absence of blood coagulation, but this is the first observation of coagulation without beta-lysin release. It is clear that beta-lysin is released from platelets during coagulation by the direct action of thrombin and that it may be released in an earlier calcium-dependent reaction.
D000818:Animals; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D002951:Citrates; D003030:Coagulase; D004492:Edetic Acid; D006493:Heparin / Q000494:pharmacology; D008239:Lysine / Q000097:blood / Q000378:metabolism*; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D009500:Neutralization Tests; D011817:Rabbits; D013917:Thrombin / Q000494:pharmacology*
D002951:Citrates; D003030:Coagulase; D006493:Heparin; D004492:Edetic Acid; D013917:Thrombin; D008239:Lysine; D002118:Calcium