Autonomic and behavioral thermoregulation in golden hamsters exposed perinatally to dioxin.
Perinatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) cause s a permanent change in thermoregulatory control of male offspring of the rat, characterized by a reduced core temperature (Tc over a wide range of ambient temperatures (Ta). To examine the similarities in this effect across species, the thermoregulatory effects of perinatal TCDD were evaluated in the golden hamster, a species which is very resistant to the lethal effects of TCDD. Adult male hamsters exposed on Gestational Day 11.5-11.75 to 2.0 microgram TCDD/kg by gavage were subjected to a variety of behavioral and autonomic thermoregulatory measurements. Nocturnal Tc of TCDD-treated animals was 0.4 to 1.0 degrees C below that of controls over a Ta range of 14 to 34 degrees C. Hypothermia persisted in spite of normal metabolic responses to cold exposure. The hypothermic effect of perinatal TCDD exposure was found to persist over a 24-hr period in unrestrained hamsters monitored by radiotelemetry. The TCDD-treated hamster offspring placed in a temperature gradient exhibited a preference for warm Ta's for 2 to 3 hr; however, when maintained over a 22-hr period in the gradient there was no effect of TCDD on behavioral thermoregulation. TCDD had no effect on motor activity measured over a 24-hr period. TCDD resulted in an approximately 30% reduction in body weight compared to controls; however, this weight loss appeared to have no bearing on the thermoregulatory deficiencies of the TCDD-treated animals. TCDD-treated hamsters displayed a normal metabolic response to cold exposure; thus, it would appear that perinatal exposure to TCDD leads to a dysfunction in the central control of body temperature. The perinatal effects of TCDD on thermoregulation in the rat and hamster appear to be similar.
Gordon
C J
CJ
Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
Yang
Y
Y
Gray
L E
LE
D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects* / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D006224:Cricetinae; D005260:Female; D008297:Male; D008647:Mesocricetus; D009043:Motor Activity / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D013686:Telemetry; D013997:Time Factors
D000072317:Polychlorinated Dibenzodioxins