Electronic Theses and Dissertations


Open Access Thesis


Activated partial thromboplastin times (APTT) and factor deficiency assays were performed on the plasma of twenty American bullfrogs (Lithobates catesbeianus) to test for potential changes and regulation of the intrinsic coagulation pathway during and after hibernation. Bullfrogs (pre-hibernating n=4, hibernating n=6, post-hibernating n=10) were housed in 10 gallon aquariums filled with RO water and placed in a temperaturecontrolled room. Hibernation was gradually induced by decreasing the temperature of the room from 24 C to 3 C in increments of 3 C per week. Blood (6-8 ml) was collected from individual non-hibernating frogs, hibernating frogs and post-hibernating frogs in 0.105M sodium citrate tubes and immediately centrifuged at 2500 x g for five minutes. The resulting plasma was stored at -80 C until tested for activated partial thromboplastin time. APTT times of hibernating bullfrogs were significantly longer than pre-hibernating times (p=0.000) and post-hibernating times (p=0.004). Factor deficient assays were performed for Factors VIII, IX, XI, and XII to determine their presence or absence. Factor VIII in all bullfrogs was either not present, or if present, was non-functional. Factor IX, XI, and XII were present in pre-hibernating bullfrogs, but during hibernation, these levels either decreased or were inhibited, suggesting that Factors IX, XI, and XII are regulated during hibernation. However, no difference in Factors IX, XI, and XII levels were found between hibernating and post-hibernating animals. Initial tests for a potential inhibitor failed to show that such an inhibitor existed, but additional studies are needed. Hibernating ectotherms, like hibernating endotherms, regulate levels of the clotting factors associated with intrinsic coagulation system during hibernation to prevent clot formation during hibernation.

Date of Award


Degree Name

Master of Science


Department of Biology

First Advisor

David Saunders, Chair, Thesis Committee

Date Original


Object Description

1 PDF file (viii, 67 pages)



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