Endocrine Abstracts

Thyroid hormone levels are strongly affected by inflammation. In a wide spectrum of diseases, ranging from critical illness in the ICU to ischemic stroke, a decrease in circulating T3 and T4 is observed without the expected increase in TSH. This disruption of the negative feedback system of the hypothalamic–pituitary–thyroid (HPT) axis is accompanied by various changes in thyroid hormone metabolism at the cellular and tissue level. C...

Background: Autoimmune hypophysitis can result in growth hormone deficiency (GHD). Although autoimmune hypophysitis is uncommon, it is associated with other autoimmune endocrine diseases like autoimmune hypothyroidism (AIH). Recent studies suggest a high prevalence (5%) of GHD in AIH, which could contribute to the reduced quality of life frequently observed in patients with AIH despite adequate treatment with thyroxine.Objective: To establish the prevale...

Pre-autonomic neurons in the hypothalamic paraventricular nucleus (PVN) project to sympathetic and parasympathetic motor nuclei in the brain stem, from where the liver and white adipose tissue (WAT) are innervated by both branches of the autonomic nervous system (ANS). Studies by our group and by others have shown that these neural pathways modulate glucose and lipid metabolism in liver and WAT. Given the abundant thyroid hormone receptor (TR) expression in the PVN we hypothes...

Fasting induces profound metabolic changes in order to decrease energy expenditure and to conserve energy. One of the major adaptations is downregulation of the hypothalamus–pituitary–thyroid (HPT) axis, characterized by decreased serum thyroid hormone levels without an increase in serum TSH or in TRH expression in the hypothalamic paraventricular nucleus (PVN). Leptin has been proposed as a critical signal initiating the neuroendocrine response to fasting as it decr...

Background: Hypothyroidism is a common endocrine disorder and the standard treatment is replacement therapy with levothyroxine (LT4). Although many hypothyroid patients improve upon treatment with LT4, a proportion seems to experience residual hypothyroid complaints despite treatment, even when plasma TSH and FT4 are within reference ranges.Methods: Using an on-line survey we investigated i) the health-related quality of life (QoL) (ThyPRO), ii) the acti...

Rationale: A history of optic chiasm compression in patients treated for sellar tumors is associated with alterations in sleep-wake rhythm. The optic chiasm contains axons of intrinsically photosensitive retinal ganglion cells (ipRGCs) that mediate photoentrainment of the suprachiasmatic nucleus. Compression could disrupt this entrainment leading to desynchronization with the 24-hour light-dark cycle. The post-illumination pupil response (PIPR) after blue light exposure is a u...

Context: Loss-of-function of immunoglobulin superfamily 1 (IGSF1) causes an X-linked syndrome of central hypothyroidism, macroorchidism, and variable prolactin deficiency, GH deficiency in childhood, delayed pubertal testosterone rise, and/or obesity. The clinical features advert towards a pivotal role for IGSF1 in the pituitary gland, but detailed knowledge on pituitary hormone secretion in this syndrome is lacking.Objective: To study detailed ...

Background: Clinically non-functioning pituitary macroadenomas (NFMA) have been reported to express various somatostatin receptor (SSTR) subtypes, but results are inconsistent across different studies. This may be related to limited sensitivity and specificity of techniques used to date, i.e. immunohistochemistry in surgical specimens and 111In-DTPA-octreotide scintigraphy (Octreoscan) in vivo. The aim of this study was to assess SSTR expression in NFMA <em...

Introduction: In patients with ACTH-dependent hypercortisolism, the corticotropin-releasing-hormone (CRH) test and the high dose dexamethasone suppression test (HDDST) can be used to differentiate between pituitary ACTH production (Cushing’s disease) and ectopic ACTH production. The rationale is that a pituitary adenoma will show some response to CRH and ACTH whereas an ectopic source is less responsive to ACTH and CRH. However, there is discussion about the clinical util...

Rationale: At present, there is no approved medical treatment for patients with clinically non-functioning pituitary adenoma. A number of open-label studies suggest that treatment with somatostatin analogues may prevent tumour progression in selected patients. In vivo assessment of somatostatin receptor status using 68Ga-DOTATATE PET could help to select patients responsive to treatment.Trial objective: To investigate the effect of the somatosta...