title: Plasma corticosterone response in continuous versus discontinuous chronic heat exposure in rat.
abstract: Effects of chronic exposure (25 days) to continuous (CHE) or discontinuous (DHE) hot environment (34 degrees C) on growth rate, food intake and cortico-adrenal function were studied in adult male rats. Growth rate and food intake were 40 and 31% less respectively in CHE and 7 and 9% less respectively in DHE than in control (CE) animals. The adrenal response to heat (40 degrees C) was reduced by 54 and 82% in CHE and DHE rats respectively but the plasma corticosterone (B) response to exogenous ACTH and ether stress was not altered by chronic heat. The plasma B rhythm was altered only in CHE rats which exhibited a 40% decrease in amplitude and a delayed nocturnal recession of plasma B values. These results indicate that 1) CHE induced major alterations of behavior specially during the nocturnal period of the L-D cycle, 2) that the altered circadian B rhythm of CHE rats could be linked to changes in feeding behavior and to reduced metabolic activity, 3) and that CHE induced a poorer adaptation than DHE.
authors.affiliation: Centre de Recherches due Service de Santé des Armées, Unité de Bioénergétique et Environment, La Tronche.
authors.forename: M
authors.initials: M
authors.lastname: Cure
mesh_terms: D000222:Adaptation, Physiological; D000311:Adrenal Glands / Q000033:anatomy & histology; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D002908:Chronic Disease; D002940:Circadian Rhythm / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D004986:Ether / Q000008:administration & dosage / Q000009:adverse effects; D005247:Feeding Behavior / Q000502:physiology*; D006358:Hot Temperature / Q000009:adverse effects*; D009929:Organ Size; D010507:Periodicity; D051381:Rats; D011919:Rats, Inbred Strains; D013312:Stress, Physiological / Q000097:blood* / Q000139:chemically induced / Q000503:physiopathology; D013997:Time Factors; D015430:Weight Gain / Q000502:physiology
chemical_list: D004986:Ether; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone