title: Effects of thyroxine and naloxone administration on metabolism and ventilation in hamsters.
abstract: This study examined the interaction between hyperthyroidism and opioid receptor function on control of ventilation and metabolism in male Harlan hamsters 4 and 8 weeks after implanting thyroxine (T(4)) or placebo pellets. Metabolism, but not body temperature, increased in T(4)-treated hamsters relative to placebo-treated animals. After 4 weeks, body weights were greater in the T(4)-treated hamsters, but comparable to controls after 8 weeks. At that time, body length was greater in T(4)-treated hamsters than in controls. Thyroxine did not affect ventilation in air or in response to CO(2). Naloxone, an opioid receptor antagonist, decreased metabolism in T(4)-treated, but not in placebo-treated hamsters without affecting ventilation in air in either group. In the placebo group naloxone augmented the ventilatory response to hypercapnia by increasing frequency. These results negate our hypotheses that: (1) hyperthyroid hamsters exhibit greater ventilation in air and in response to hypercapnia than controls; and (2) that naloxone augments these effects.
authors.affiliation: Neuroscience Group, Division of Basic Biomedical Sciences, University of South Dakota, 414 E. Clark Street, Vermillion, SD 57069, USA.
authors.forename: E H
authors.initials: EH
authors.lastname: Schlenker
authors.forename: J A
authors.initials: JA
authors.lastname: Burbach
authors.forename: Y N
authors.initials: YN
authors.lastname: Singh
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000097:blood; D006224:Cricetinae; D004343:Drug Implants; D008297:Male; D008647:Mesocricetus; D008660:Metabolism / Q000187:drug effects*; D009270:Naloxone / Q000008:administration & dosage / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D015656:Respiratory Mechanics / Q000187:drug effects*; D013974:Thyroxine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D013990:Tidal Volume / Q000187:drug effects; D014284:Triiodothyronine / Q000097:blood
chemical_list: D004343:Drug Implants; D009292:Narcotic Antagonists; D014284:Triiodothyronine; D002245:Carbon Dioxide; D009270:Naloxone; D013974:Thyroxine