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THE EFFECTS OF CHRONIC EXERCISE CONDITIONING ON THERMOREGULATORY RESPONSE TO CHLORPYRIFOS IN FEMALE RATS.
Citation:
Rowsey, P J., B. L. Metzger, AND C J. Gordon. THE EFFECTS OF CHRONIC EXERCISE CONDITIONING ON THERMOREGULATORY RESPONSE TO CHLORPYRIFOS IN FEMALE RATS. Presented at Experimental Biology, Orlando, FL, 3/30/2001-4/3/2001.
Description:
Chronic exercise conditioning has been shown to alter basal thermoregulatory processes (change in thermoregulatory set-point) as well as the response to infectious fever. Chlorpyrifos (CHP), an organophosphate pesticide, causes an acute period of hypothermia followed by a delayed fever lasting for several days. We assessed if chronic exercise training in the rat would alter the thermoregulatory response to chlorpyrifos. Core temperature (Tc) and motor activity were monitored by radiotelemetry. Female Sprague Dawley rats at 45 days of age weighing 90-110 g were divided into two groups: exercise (EXER) and sedentary (SED) and housed individually at an ambient temperature (Ta) of 22 EC. To be assured of a definite Atraining@ effect, EXER animals were given free access to a running wheel for 8 weeks. EXER and SED rats were then randomly divided into CHP or corn oil (CO) groups. Rats were gavaged with corn oil or 15 mg/kg CHP. Tc decreased similarly by 1.6 EC in SED and EXER groups given CHP. The next day, the SED CHP group developed a higher fever than the EXER CHP group; 1.0 EC and 0.3 EC above baseline, respectively. The fever of EXER CHP group recovered within 24 hr (one day later). The SED CHP group had a fever for 48 hr (0.5 EC day 2 and day 3 post- injection). Overall, exercise training did not provide protection from the hypothermic effects of CHP. However, EXER animals exposed to CHP showed enhanced resistance (protective effect) by displaying a smaller fever when compared to their SED counterparts. Thus, chronic exercise training may be beneficial in response to exposure to organophosphates. This abstract does not necessarily reflect US EPA policy.