Thyroid hormones neuronal differentiation

Little is known about the mechanism of action of thyroid hormones on microtubule assembly. It might be that, as in other cell types, thyroid hormones regulate the expression of the specific TAU mRNAs and/or their accumulation. One has also to take into account that a large number of other molecules are required to build up neurites during neuronal differentiation (membranes, components of the growth cone, etc.). 

Thus, some endogenous small molecular compounds that are able to mimic the biological effect of the natural neurotrophic factors, or to stimulate their synthesis and secretion, might be promising candidates for pharmaceutical agents of various neurodegenerative diseases. Sex hormones, thyroid hormones, vitamin D and their derivatives are already known to affect survival and differentiation of dissociated mouse embryo brain in cultures or in cultured rat septal neurons. However, application of these hormones to patients with normal hormone function... 

Aizenmann, Y. and de Vellis, J. (1987) Brain neurons develop in a serum and glial free environment effects of transferrin, insulin, insulin-like growth factor 1 and thyroid hormone on neuronal survival, growth and differentiation. Brain Res. 406 32-42. 

Altered migration and differentiation of neurons Cell migration - cerebellum Cerebral cortex and hippocampus Stunted dendritic and axonal growth and maturation Purkinje cells Dendritic spine number Delayed and poor deposition of myelin Reduced axonal number Thyroid hormone receptors... 

Thyroid hormone deficiency during the development of CNS alters nerve cells, such as the pyramidal and Purkinje cells, and induces glial cell profiferation and differentiation. Under such conditions, neurons become hypoplastic, and have reduced axonal count, dendritic branching, synaptic spikes and interneuronal connections. 

Thyroid hormones regulate processes of terminal brain differentiation, such as dendritic and axonal growth, synaptogen-esis, neuronal migration and myefination. They also modulate... 

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