title: Withdrawal From Chronic Nicotine Reduces Thyroid Hormone Levels and Levothyroxine Treatment Ameliorates Nicotine Withdrawal-Induced Deficits in Hippocampus-Dependent Learning in C57BL/6J Mice.
abstract: BACKGROUND
  Cigarette smoking alters a variety of endocrine systems including thyroid hormones. Altered thyroid hormone signaling may lead to a subclinical or overt hypothyroid condition that could contribute to nicotine withdrawal-related symptoms, such as cognitive deficits. Thus, normalizing thyroid hormone levels may represent a novel therapeutic target for ameliorating nicotine withdrawal-associated cognitive deficits.
  
  
  METHODS
  The current studies conducted an analysis of serum thyroid hormone levels after chronic and withdrawal from chronic nicotine treatment in C57BL/6J mice using an enzyme-linked immunosorbent assay. The present studies also evaluated the effect of synthetic thyroid hormone (levothyroxine) on contextual and cued memory.
  
  
  RESULTS
  The current studies found that nicotine withdrawal reduces secreted thyroid hormone levels by 9% in C57BL/6J mice. Further, supplemental thyroid hormone not only enhanced memory in naïve animals, but also ameliorated deficits in hippocampus-dependent learning associated with nicotine withdrawal.
  
  
  CONCLUSIONS
  These results suggest that smokers attempting to quit should be monitored closely for changes in thyroid function. If successfully treated, normalization of thyroid hormone levels may ameliorate some deficits associated with nicotine withdrawal and this may lead to higher rates of successful abstinence.
authors.affiliation: Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA.
authors.forename: Prescott T
authors.initials: PT
authors.lastname: Leach
authors.affiliation: Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA.
authors.forename: Erica
authors.initials: E
authors.lastname: Holliday
authors.affiliation: Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA.
authors.forename: Munir G
authors.initials: MG
authors.lastname: Kutlu
authors.affiliation: Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA tgould@temple.edu.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Gould
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects*; D005239:Fear / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects*; D007037:Hypothyroidism / Q000097:blood* / Q000523:psychology; D007858:Learning / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009538:Nicotine / Q000009:adverse effects / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000009:adverse effects / Q000494:pharmacology*; D013375:Substance Withdrawal Syndrome / Q000097:blood* / Q000209:etiology / Q000523:psychology; D013961:Thyroid Gland / Q000187:drug effects*; D013963:Thyroid Hormones / Q000097:blood / Q000494:pharmacology; D013974:Thyroxine / Q000097:blood / Q000494:pharmacology*; D014029:Tobacco Use Disorder
chemical_list: D018722:Nicotinic Agonists; D013963:Thyroid Hormones; D009538:Nicotine; D013974:Thyroxine