Diminished gray matter within the hypothalamus in autism disorder: a potential link to hormonal effects?

BACKGROUND: Subjects with autism suffer from impairments of social interaction, deviations in language usage, as well as restricted and stereotyped patterns of behavior. These characteristics are found irrespective of age, IQ, and gender of affected subjects. However, brain changes due to age, IQ, and gender might pose potential confounds in autism neuroimaging analyses. METHODS: To investigate gray matter differences in autism that are not related to these potential confounds, we performed a voxel-based morphometry analysis in 52 affected children and adolescents and 52 matched control subjects. RESULTS: We observed diminished gray matter in a region of the hypothalamus, which synthesizes the behaviorally relevant hormones oxytocin and arginine vasopressin. CONCLUSIONS: This finding provides support for further investigations of the theory of abnormal functioning of this hormonal system in autism and potentially for experimental therapeutic approaches with oxytocin and related neuropeptides.

Neurohypophysial peptides in the human hypothalamus in relation to development, sexual differentiation, aging and disease.

The two neuronal systems that contain neurohypophysial peptides in the hypothalamus i.e. (i) the supraoptic and paraventricular nucleus and (ii) the suprachiasmatic nucleus, show quite different patterns of changes in the human in relation to development, aging and disease.

Neuroendocrine gene expression in the hypothalamus: in situ hybridization histochemical studies.

1. We have reviewed recent studies in which in situ hybridization histochemistry (ISHH) was used to investigate the regulation of expression of neurohypophysial peptides and hypothalamic releasing hormones. 2. ISHH is a technique in which the presence and quantity of a specific mRNA can be determined in tissue sections with a high degree of resolution and sensitivity. 3. ISHH has been used to measure changes in cellular levels of mRNAs encoding vasopressin, oxytocin, corticotropin-releasing factor, gonadotropin-releasing hormone, thyrotropin-releasing hormone and somatostatin in response to various physiological challenges. 4. A theme emerging from these studies is that changes in levels of mRNA encoding neuroendocrine peptides reflect changes in biosynthesis and secretion.

Role of the central nervous system neuropeptides in body fluid homeostasis.

Several peptides are produced by central nervous system neurons, many of these are involved in the control of body fluid homeostasis. The presence of neuropeptides in the median eminence and circumventricular organs, in the neurosecretory hypothalamic cell groups and in the baroreceptor centres are briefly summarized.

Neurohormonal control of gonadotropic secretion in primates.

With immunohistochemical techniques, products from both the parvicellular system (such as Gn-RH) and from the magnocellular system (vasopressin, oxytocin, and neurophysins) have been shown to be present in the neurons ending around the hypothalamopituitary portal capillary system. A neurosurgical technique for prolonged collection of pituitary stalk blood has been developed. Gn-RH, vasopressin, and neurophysins have been found in large amounts in pituitary stalk blood. Gn-RH levels were found to vary in a pulsatile fashion, thereby providing direct evidence for hypothalamic modulation of the discharge of LH by the pituitary. The finding of large amounts of estrogen-neurophysin in portal vein blood adds further evidence to the hypothesis that "estrogen" neurophysin may play a role in the control by the hypothalamus over the secretion of gonadotropins.