title: Leptin-programmed rats respond to cold exposure changing hypothalamic leptin receptor and thyroid function differently from cold-exposed controls.
abstract: We showed that neonatal leptin treatment programmes for hyperleptinemia and central leptin resistance both at 30days-old and adulthood, while programmes for lower serum T3 at 30days-old, but higher thyroid hormones (TH) at adulthood. As in these animals, acute cold at 30days-old normalized leptinemia and restored the expression of hypothalamic leptin receptor (OBR), here we evaluate the effect of cold exposure on the thyroid function and OBR in adult rats programmed by neonatal hyperleptinemia. Pups were divided into 2 groups: Lep-injected with leptin (8μg/100g/BW, sc) for the first 10days of lactation, and C-injected with saline. At 150days, both groups were subdivided into: LepC and CC, which were exposed to 8°C for 12h. Serum leptin, TH, TSH, liver type I and brown adipose tissue (BAT) type II deiodinases (D1 and D2) activities, liver mitochondrial alpha-glycerol-3-phosphate dehydrogenase (mGPD) activity and adrenal catecholamine content were measured. Hypothalamic and thyroid OBR protein contents were evaluated. Differences were significant when p<0.05. Lep group had hyperleptinemia (+19%), higher T4 (+20%) and T3 (+30%) with lower TSH (-55%), higher liver D1 (1.4 fold-increase), lower BAT D2 (-44%) and liver mGPD activities (-55%), higher adrenal catecholamines (+44%), lower hypothalamic OBR (-51%) and normal thyroid OBR. Cold exposure normalized leptinemia, D1, mGPD, catecholamine and hypothalamic OBR. However, cold exposure further increased TH and decreased D2. Thus, cold exposure normalizes most of the changes programmed by neonatal hyperleptinemia, at the expense of worsening the hyperthyroidism and BAT thermogenesis.
authors.affiliation: Department of Nutrition, Federal University of Juiz de Fora, Minas Gerais, MG, Brazil.
authors.forename: Sheila Cristina Potente
authors.initials: SC
authors.lastname: Dutra
authors.forename: Egberto Gaspar
authors.initials: EG
authors.lastname: de Moura
authors.forename: Patricia Cristina
authors.initials: PC
authors.lastname: Lisboa
authors.forename: Isis Hara
authors.initials: IH
authors.lastname: Trevenzoli
authors.forename: Magna Cottini Fonseca
authors.initials: MC
authors.lastname: Passos
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000378:metabolism; D003080:Cold Temperature / Q000009:adverse effects*; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D007453:Iodide Peroxidase / Q000378:metabolism; D020738:Leptin / Q000008:administration & dosage*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D054411:Receptors, Leptin / Q000378:metabolism*; D013312:Stress, Physiological; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000378:metabolism
chemical_list: D002395:Catecholamines; D020738:Leptin; D054411:Receptors, Leptin; D013963:Thyroid Hormones; D005993:Glycerolphosphate Dehydrogenase; D007453:Iodide Peroxidase