Thermoregulation in Rats Exposed Perinatally to Dioxin: Core Temperature Stability to Altered Ambient Temperature, Behavioral Thermoregulation, and Febrile Response to Lipopolysaccharide

Details

• Personal Author:
  Gordon CJ ; Miller DB
• Description:
  Recent studies have shown that perinatal exposure to 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD, dioxin) alters thermoregulatory function in adult rats and hamsters, indicated by a reduced body temperature during the animal's nocturnal phase. The present study was designed to assess the behavioral thermoregulation, ability to develop a fever, and thermoregulatory stability as a function of ambient temperature (Ta) in rats exposed perinatally to TCDD. Pregnant Long-Evans rats were exposed on gestational day (GD) 15 to 1 mug TCDD/kg (po). The male offspring were implanted with transmitters to monitor core temperature (Tc) and motor activity (MA). The 24-h pattern of core temperature was affected by TCDD exposure, characterized by a reduced nocturnal Tc. At some ages, the diurnal Tc of the TCDD group was elevated. This dysfunction in temperature regulation was most apparent at 7 and 11 mo of age. The 24-h pattern of MA was also altered by TCDD. The hypothermic effects of TCDD were most pronounced at cooler T values a of 10 to 22 C. In contrast, behavioral thermoregulation, assessed by measuring the selected Ta and Tc of rats in a temperature gradient, was unaffected by TCDD. The ability to develop a fever following administration of lipopolysaccharide (LPS) endotoxin (Escherichia coli; 50 mug/ kg) was accentuated in the TCDD-treated animals. The data confirm a nocturnal hypothermia in rats prenatally exposed to TCDD. However, the normal behavioral regulation of Tc suggests that hypothalamic thermoregulatory centers are not permanently altered. The accentuated fever in TCDD animals shows possible functional alterations in the neuroimmune and/or thermoregulatory axes involved in fever. [Description provided by NIOSH]
• Subjects:
  Animals Dioxins Laboratories Occupational Health Safety Temperature
• Keywords:
  Animal-studies Laboratory-animals Temperature-control Temperature-effects Temperature-measurement Thermoregulation
• ISSN:
  0098-4108
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  54
• Issue:
  8
• NIOSHTIC Number:
  nn:20025000
• Citation:
  J Toxicol Environ Health A 1998 Aug; 54(8):647-662
• Contact Point Address:
  Dr. C. J. Gordon, MD-74B, U.S. EPA, Research Triangle Park, NC 27711, USA
• Email:
  gordon@herl45.herl.epa.gov
• CAS Registry Number:
  2,3,7,8-Tetrachlorodibenzo-p-dioxin (CAS RN 1746-01-6)
• Federal Fiscal Year:
  1998
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Toxicology and Environmental Health, Part A: Current Issues
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:8821f4656929e742c81b9a3d9fa1efe5b5f26f3b44b2125eedbb24aef859c11eb4dce6fce6fdf679d860279c8fcf9ac35c2ce49ed723aeb633240d24812ef8a2
• Download URL:
  https://stacks.cdc.gov/view/cdc/196534/cdc_196534_DS1.pdf
• File Type:
  [PDF - 1.05 MB ]