Role of thyroid hormone in brain development and behavior

A study, led by Bjorn Vennstrom at the Karolinska Institute ( Sweden ), has identified novel neural functions of thyroid hormone ( TH ), revealing that it is required during discrete periods of brain development to confer “normal” behavior.

The researchers used transgenic mice heterozygous for a mutant form of the thyroid hormone receptor alpha1 that has about a ten-fold reduced affinity for its natural ligand, TH.

They observed that reduced TH signaling during development lead to distinct neurological abnormalities in adulthood: extreme anxiety, reduced memory and locomotor dysfunction.

The anxiety and memory impairment could be suppressed through dietary supplementation of the adult mice with TH ( supplementation was not effective when administered as a juvenile ).

Conversely, the uncoordination could be normalized through TH injections at juvenile ( but not adult ) stages.

Since most psychiatric diseases are thought to have a polygenic background, these discoveries may have valuable implications for the diagnosis and treatment of certain mood disorders.

The results were published in the journal Genes & Development.

Source: Karolinska Institutet, 2005