Fourth ventricular thyrotropin induces satiety and increases body temperature in rats.
Am J Physiol Regul Integr Comp Physiol
; 314(5): R734-R740, 2018 05 01.
Article
em En
| MEDLINE
| ID: mdl-29351420
Besides its well-known action to stimulate thyroid hormone release, thyrotropin mRNA is expressed within the brain, and thyrotropin and its receptor have been shown to be present in brain areas that control feeding and gastrointestinal function. Here, the hypothesis that thyrotropin acts on receptors in the hindbrain to alter food intake and/or gastric function was tested. Fourth ventricular injections of thyrotropin (0.06, 0.60, and 6.00 µg) were given to rats with chronic intracerebroventricular cannulas aimed at the fourth ventricle. Thyrotropin produced an acute reduction of sucrose intake (30 min). The highest dose of thyrotropin caused inhibition of overnight solid food intake (22 h). In contrast, subcutaneous administration of corresponding thyrotropin doses had no effect on nutrient intake. The highest effective dose of fourth ventricular thyrotropin (6 µg) did not produce a conditioned flavor avoidance in a standardized two-bottle test, nor did it affect water intake or gastric emptying of glucose. Thyrotropin injected in the fourth ventricle produced a small but significant increase in rectal temperature and lowered plasma levels of tri-iodothyronin but did not affect plasma levels of thyroxine. In addition, there was a tendency toward a reduction in blood glucose 2 h after fourth ventricular thyrotropin injection ( P = 0.056). In conclusion, fourth ventricular thyrotropin specifically inhibits food intake, increases core temperature, and lowers plasma levels of tri-iodothyronin but does not affect gastromotor function.
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Base de dados:
MEDLINE
Assunto principal:
Resposta de Saciedade
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Regulação da Temperatura Corporal
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Rombencéfalo
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Tireotropina
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Ingestão de Alimentos
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Comportamento Alimentar
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article