In vivo effects of Agkistrodon rhodostoma venom: studies with fibrinogen-131I.

Abstract

Sublethal doses of the venom (13 [mu]g per kg body wt), when given intravenously to rabbits, produced a rapid disappearance of fibrinogen-l131 from the plasma followed by a partial re-appearance and then by a final steep decline of protein-bound radioactivities. Fibrinogen-I131albumin - I132 activity ratios in several tissues, especially in lung, muscle, liver and spleen, were considerably higher than those to the blood of the main vessels at the same time, suggesting that the venom acts in vivo primarily by forming mlcroclots. Radioautographic and histological examinations confirmed this. Preventive hepartoization and hypoprothrombinemia were valueless. Antifibrinolytic agents ([epsilon] -aminocaproic acid and soybean trypsin inhibitor) increased mortality significantly. After the full onset of the flbrinolytic response, the animals developed a secondary coagulation anomaly, presumed to be due to excess quantities of fibrin breakdown products in the circulation. The chromatographl-cally isolated lytic component of the venom when given in proportional amounts to the unfractioned venom, had only minute effects on the turnover of fibrinogen I131 . High doses of the same fraction, however, resulted in fibrinogenolysis.