Frequent blood sampling via intraatrial cannula revealed daily rhythms of TSH and thyroid hormones in both male and female Wistar rats. Thermic ablation of the biological clock, i.e. the suprachiasmatic nucleus (SCN), eliminated the diurnal peak in circulating TSH and thyroid hormones. In addition, SCN lesions produced a clear decrease of 24-h mean T4 concentrations. A more pronounced effect of SCN-lesions on thyroid hormones, as opposed to TSH, suggested routes of SCN control additional to the neuroendocrine hypothalamopituitary-thyroid axis. Retrograde, transneuronal virus tracing was used to identify the type and localization of neurons in the central nervous system that control the autonomic innervation of the thyroid gland. In the spinal cord and brain stem, both the sympathetic and parasympathetic motorneurons were labeled. By varying the postinoculation survival time, it was possible to follow the viral infection as it proceeded. Subsequently, the pseudorabies virus (PRV) infected neurons in several brain stem cell groups, the paraventricular nucleus of the hypothalamus (PVN) and the central nucleus of the amygdala (second order labeling). Among PRV-infected neurons in the PVN were TRH-containing cells. Third order neurons were found in several hypothalamic cell groups, among which was the SCN. Therefore, we propose that the SCN has a dual control mechanism for thyroid activity by affecting neuroendocrine control of TSH release on the one hand and the autonomic input to the thyroid gland on the other.

Cortisol excess appears to have an additional impact on cardiac remodeling in patients with PA. Treatment of PA by either adrenalectomy or mineralocorticoid receptor antagonist improves LVMI. This effect was most pronounced in patients with high total glucocorticoid excretion.

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Primary aldosteronism is a natural model for chronic aldosterone excess in humans and associated with symptoms of anxiety and depression. Cognitive deficits are inherent to the symptomatology of depression and anxiety disorders. Mineralocorticoid receptors and aldosterone appear to play a role in memory. Aldosterone was additionally supposed to be a risk factor for cognitive decline in patients with essential hypertension. The objective of this study was to investigate possible effects of chronically high aldosterone concentrations on cognitive function. A range of cognitive dimensions were assessed in 19 patients (9 males, 10 females); mean age 47.1 (12.5) under standardized treatment and several rating scales for anxiety, depression, quality of life and sleep were administered. Cognitive parameters were compared to standard norms from a large, healthy standardization sample. Patients showed increased levels of anxiety and depression without meeting diagnostic criteria for a disorder. Besides a numerically lower attention score, patients did not show any significant differences in the cognitive dimensions. Anxiety and depression were negatively correlated with quantitative performance in males. In females, a negative correlation between sleep disturbances and abstract reasoning and a positive correlation with quantitative performance were found. Our data showed no specific effect of chronic aldosterone in the tested cognitive parameters overall at least in younger patients, but they indicate sexually dimorphic regulation processes.

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