[Acceleration of the initial stages of thrombin clearance in the bloodstream of rats during stress].

In a stress due to 30-min immobilization, the initial stages of the thrombin clearance in the blood flow of rats are considerably accelerated. Thus, in 5 min after i.v. administration of thrombin I131, The blood relative radioactivity in experimental rats decreases by about 40% while in the control animals--by 20%. The same stress against the background of exogenous ACTH leads to a still greater acceleration of the thrombin clearance and the blood relative radioactivity within the 5 min decreases by 55%. The accelerated clearance of the thrombin I131 from the blood during immobilization and combination of the latter with ACTH administration is followed by its accumulation in the liver and its reduction in the lungs. The activating effect of ACTH on the thrombin I131 clearance is not, apparently, mediated through activation of the adrenal glucocorticoid function as the clearance initial stages are not accelerated after hydrocortisone administration. The clearance depends on the heparin contents in the blood: binding of endogenous heparin with protamine--sulphate leads to abolishing of the stress activating effect, and the speed of clearance in immobilized animals decreases to basal level of control animals.