Hypo- and hyperthyroidism affect NEI concentration in discrete brain areas of adult male rats

To date, there has been only one in vitro study of the relationship between neuropeptide EI (NEI) and the hypothalamic-pituitary-thyroid (HPT) axis. To investigate the possible relationship between NEI and the HPT axis, we developed a rat model of hypothyroidism and hyperthyroidism that allows us to determine whether NEI content is altered in selected brain areas after treatment, as well as whether such alterations are related to the time of day. Hypothyroidism and hyperthyroidism, induced in male rats, with 6-propyl-1-thiouracil and L-thyroxine, respectively, were confirmed by determination of triiodothyronine, total thyroxine, and thyrotropin levels. All groups were studied at the morning and the afternoon. In rats with hypothyroidism, NEI concentration, evaluated on postinduction days 7 and 24, was unchanged or slightly elevated on day 7 but was decreased on day 24. In rats with hyperthyroidism, NEI content, which was evaluated after 4 days of L-thyroxine administration, was slightly elevated, principally in the preoptic area in the morning and in the median eminence-arcuate nucleus and pineal gland in the afternoon, the morning and afternoon NEI contents being similar in the controls. These results provide the bases to pursue the study of the interaction between NEI and the HPT axis. (C) 2011 Elsevier Inc. All rights reserved.

Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET)

Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET)

Fondos para la Investigacion Cientifica y Tecnologica (FONCyT)

Fondos para la Investigacion Cientifica y Tecnologica (FONCyT)

Secretaria de Ciencia y Tecnica (SECyT-Universidad Nacional de Cordoba)

Secretaria de Ciencia y Tecnica (SECyT-Universidad Nacional de Cordoba)

Secretaria de Ciencia, Tecnica y Posgrado (SeCTyP-Universidad Nacional de Cuyo), Argentina

Secretaria de Ciencia, Tecnica y Posgrado (SeCTyP-Universidad Nacional de Cuyo), Argentina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sao Paulo Research Foundation (FAPESP)[2004/13849-5]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

National Council for Scientific and Technological Development (CNPq)

Coordination for the Improvement of Higher Education (CAPES), Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)