title: Voluntary exercise adapts the hypothalamus-pituitary-thyroid axis in male rats.
abstract: The hypothalamic-pituitary thyroid (HPT) axis modulates energy homeostasis. Its activity decreases in conditions of negative energy balance but the effects of chronic exercise on the axis are controversial and unknown at hypothalamic level. Wistar male rats were exposed for up to 14 days to voluntary wheel running (WR), or pair-feeding (PF; 18% food restriction), or to repeated restraint (RR), a mild stressor. WR and RR diminished food intake; body weight gain decreased in the 3 experimental groups, but WAT mass and serum leptin more intensely in the WR group. WR, but not RR, produced a delayed inhibition of central markers of HPT axis activity. At day 14, in WR rats paraventricular nucleus-pro-TRH mRNA and serum TSH levels decreased, anterior pituitary TRH-receptor 1 mRNA levels increased, but serum thyroid hormone levels were unaltered, which is consistent with decreased secretion of TRH and clearance of thyroid hormones. A similar pattern was observed if WR animals were euthanized during their activity phase. In contrast, in PF animals the profound drop of HPT axis activity included decreased serum T3 levels and hepatic deiodinase 1 activity; these changes were correlated with an intense increase in serum corticosterone levels. WR effects on HPT axis were not associated with changes in the activity of the hypothalamic-pituitary adrenal axis, but correlated positively with serum leptin levels. These data demonstrate that voluntary WR adapts the status of the HPT axis, through pathways that are distinct from those observed during food restriction or repeated stress.
authors.affiliation: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Morelos, México.
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Uribe
authors.forename: Lorraine
authors.initials: L
authors.lastname: Jaimes-Hoy
authors.forename: Candy
authors.initials: C
authors.lastname: Ramírez-Martínez
authors.forename: Arlene
authors.initials: A
authors.lastname: García-Vázquez
authors.forename: Fidelia
authors.initials: F
authors.lastname: Romero
authors.forename: Miguel
authors.initials: M
authors.lastname: Cisneros
authors.forename: Antonieta
authors.initials: A
authors.lastname: Cote-Vélez
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Charli
authors.forename: Patricia
authors.initials: P
authors.lastname: Joseph-Bravo
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D031204:Caloric Restriction / Q000009:adverse effects; D005786:Gene Expression Regulation; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000503:physiopathology*; D020738:Leptin / Q000097:blood; D008297:Male; D009043:Motor Activity; D009474:Neurons / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018025:Receptors, Thyrotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D012149:Restraint, Physical / Q000009:adverse effects; D013312:Stress, Physiological; D013315:Stress, Psychological / Q000097:blood / Q000503:physiopathology*; D013961:Thyroid Gland / Q000378:metabolism / Q000503:physiopathology*; D013963:Thyroid Hormones / Q000097:blood / Q000378:metabolism; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D020738:Leptin; D018025:Receptors, Thyrotropin-Releasing Hormone; C535055:TRH-receptor-1, rat; D013963:Thyroid Hormones; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin