Blood coagulation and anticoagulant mechanisms in the turtle Pseudemys elegans

Abstract

1. 1. Three groups of control (warm) and three groups of experimental (cold-torpid) turtles ( Pseudemys elegans) were subjected to room temperature (21–22°C) and to low temperature (2–4°C) respectively, from 1 to 6 months. Blood coagulation was studied utilizing such standard tests as the prothrombin clotting time of plasma and the coagulation time of whole blood. An anticoagulant substance with the metachromatic staining properties of a mucopolysaccharide was extracted from plasma and an attempt was made to correlate the amount of this substance with mast cell populations of liver and duodenal tissues. 2. 2. The prothrombin clotting time of the warm and cold-torpid groups varied considerably, but the mean clotting times for the two groups were essentially identical. An absence of whole blood coagulation was noted in many animals from both warm and cold environments. It was concluded that neither the warm nor the cold-torpid animals had an apparent fibrinogen deficiency, and that the variation in the clotting time was possibly due both to other factors of the clotting process and to seasonal or other factors independent of the experimental environment. 3. 3. Mean yields for the extracted anticoagulant were 2·04 and 6·67 mg/100 ml plasma for the three groups of warm and the three groups of cold-torpid animals respectively. The yield of the anticoagulant increased with length of exposure to the experimental environment. 4. 4. No correlation was found between the quantity of the anticoagulant substance and the number of tissue mast cells in liver and duodenal tissues from warm or cold-torpid animals. Neither was correlation found between the prothrombin clotting time and the anticoagulant yield nor between the coagulation of whole blood and the anticoagulant yield.