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The thyroid hormone derivative 3-iodothyronamine increases food intake in rodents

Authors


Prof. S. R. Bloom, Department of Investigative Medicine, Faculty of Medicine, Imperial College, 6th Floor Commonwealth Building, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
E-mail:
s.bloom@imperial.ac.uk

Abstract

Background:  The thyroid hormone derivative 3-iodothyronamine (T1AM), an endogenous biogenic amine, is a potent agonist of the G protein–coupled trace amine-associated receptor 1 (TAAR1). T1AM is present in rat brain, and TAAR1 is expressed in hypothalamic nuclei associated with the regulation of energy homeostasis.

Aim:  The aim of this study was to determine the effects of T1AM on food intake in rodents.

Methods:  We determined the effect of (i) intraperitoneal (i.p.) administration of T1AM on food intake, oxygen consumption (VO2) and locomotor activity in mice; (ii) intracerebroventricular (ICV) injection of T1AM on food intake in male rats; (iii) c-fos expression following ventricular administration of T1AM in male rats; and (iv) direct injection of T1AM into the arcuate nucleus (ARC) of male rats on food intake.

Results:  (i) T1AM (4 nmol/kg) significantly increased food intake following i.p. injection in mice but had no effect on VO2 or locomotor activity. (ii) ICV administration of T1AM (1.2 nmol/kg) significantly increased food intake in male rats. (iii) Intraventricular administration of T1AM significantly increased c-fos expression in the ARC of male rats. (iv) Direct administration of T1AM (0.12, 0.4 and 1.2 nmol/kg) into the ARC of male rats significantly increased food intake.

Conclusion:  These data suggest that T1AM is an orexigenic factor that may act through the ARC to increase food intake in rodents.

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