Activated clotting time and heparin administration in Sprague-Dawley rats and Syrian golden hamsters.

To determine the activated clotting time (ACT) in rats and hamsters from our colony and to evaluate the response of this parameter to different heparin doses in these species, ACTs were measured using a Medtronic HemoTec ACT measurement system in samples obtained by intracardiac puncture from normal, nonanticoagulated, anesthetized rats and hamsters. Another groups of animals received different intravenous boluses of heparin to determine the dose needed to maintain ACT values > 480 sec for at least 30 min. The ACT (mean +/- SEM) was 48.