Thyroid Hormone in the Regulation of Neurotransmitter Function and Behaviour

Abstract

Recent developments in the field of psychoneuroendocrinology have led to the suggestion that neuroendocrine strategies represent a useful approach for evalu­ating brain function during psychiatric illnesses. Studies have revealed that there are significant alterations in the levels of circulating hormones during affective disorders and psychoses. Since evidence also indicates that hormones affect the metabolism of putative neurotransmitters, it is likely that changes in the mental state during certain endocrine disorders might be the sequelae of alterations in the central monoamine metabolism produced by altered levels of hormones. Additionally, it has been shown that neurotransmitters such as catecholamines and indoleamine play a major role in the regulation of neuroendocrine function. Hence, it is important to determine which of the two abnormalities (i.e., changes in hormonal secretion induced by altered levels of central amines or aberrant metabolism of putative neurotransmitters induced by altered hormonal levels) has the prime role in the pathophysiology of these psychiatric illnesses.