[Thyroid hormone therapy in old age]. / Therapie mit Schilddrüsenhormonen im Alter.

BACKGROUND: There is evidence that the treatment of overt hyperthyroidism with thyroid hormones is able to reduce mortality as well as cardiovascular and musculoskeletal morbidity. It remains unclear whether these data can be extrapolated to the mildest form of hypothyroidism, subclinical hypothyroidism. Furthermore, it is uncertain whether and to what extent the threshold for therapeutic intervention needs to be modified in the elderly, in whom hypothalamo-pituitary regulation is increasingly insensitive to the negative feedback by thyroid hormones and the patients' response to thyroid hormones changes. OBJECTIVE: The aim of this review is to evaluate the current evidence on the treatment of hypothyroidism in old age with regard to the initiation of therapy and the therapeutic goals. RESULTS AND CONCLUSIONS: According to new original data and meta-analyses, therapy with thyroid hormones does not alter morbidity and mortality in patients with subclinical hypothyroidism with thyroid stimulating hormone (TSH) below the range of 7-10 mU/l. These data support the TSH threshold of 10 mU/l recommended in guidelines, particularly in elderly patients over the age of 65 years, in whom TSH serum levels increase with age. In contrast to the recommendations, the prescription of thyroxine more than doubled in a large study from Denmark and TSH levels decreased from 10 mU/l to under 7 mU/l between 2001 and 2015. As (the primarily unspecific) symptoms and quality of life are not altered by thyroxine replacement in studies on subclinical hypothyroidism and elderly patients are more susceptible to side effects, thyroid hormone substitution should generally not be started at TSH levels <10 mU/l.

Gender-specific co-activation of arginine vasopressin and the hypothalamic-pituitary-adrenal axis during stress.

OBJECTIVE: To study the interaction between copeptin and hypothalamic-pituitary-adrenal (HPA) activation in men and women during hypoglycaemic stress. DESIGN AND PATIENTS: A prospective study in 118 patients (mean age 47·7 ± 13·6 years, n = 52 women) undergoing insulin tolerance testing for suspected pituitary dysfunction. MEASUREMENTS: Serum copeptin was measured in serially collected blood samples and assessed in relation to ACTH, cortisol and other endocrine parameters. RESULTS: Symptomatic hypoglycaemia (mean glucose nadir, 1·6 ± 0·5 mmol/l) resulted in a rapid significant increase of serum copeptin. Individuals with impaired pituitary function had lower stress-induced copeptin levels (median, 6·26 pmol/l) than patients with intact pituitary (8·46 pmol/l, P < 0·001). A weak overall correlation between stress-induced copeptin and cortisol levels was observed (rs  = 0·31, P < 0·001). In female individuals, there was a positive correlation between stress-induced copeptin and ACTH (rs  = 0·47, P < 0·001) or cortisol levels (rs  = 0·42, P = 0·002), while in males, no correlation with ACTH levels (rs  = 0·03, P = 0·75) and poor correlation with cortisol levels (rs  = 0·24, P = 0·045) was observed. Patients with central diabetes insipidus showed lowest baseline (2·20 pmol/l) and stimulated copeptin levels (3·68 pmol/l). CONCLUSIONS: The data from this study indicate that stress-induced release of AVP in women, but not in men, is linked to the co-activation of the hypothalamic-pituitary-adrenal system.

Headache and pituitary disease: a systematic review.

Headache is very common in pituitary disease and is reported to be present in more than a third of all patients with pituitary adenomas. Tumour size, cavernous sinus invasion, traction or displacement of intracranial pain-sensitive structures such as blood vessels, cranial nerves and dura mater, and hormonal hypersecretion are implicated causes. The present review attempts to systematically review the literature for any combination of headache and pituitary or hormone overproduction or deficiency. Most data available are retrospective and/or not based on the International Headache Society (IHS) classification. Whereas in pituitary apoplexy a mechanical component explains the almost universal association of the condition with headaches, this correlation is less clear in other forms of pituitary disease and a positive impact of surgery on headaches is not guaranteed. Similarly, invasion into the cavernous sinus or local inflammatory changes have been linked to headaches without convincing evidence. Some studies suggest that oversecretion of GH and prolactin may be important for the development of headaches, and treatment, particularly with somatostatin analogues, has been shown to improve symptoms in these patients. Otherwise, treatment rests on general treatment options for headaches based on an accurate clinical history and a precise classification which includes assessment of the patient's psychosocial risk factors.

Severe early-onset obesity, adrenal insufficiency and red hair pigmentation caused by POMC mutations in humans.

Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin. While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far. Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5) and the linkage of human obesity to chromosome 2 in close proximity to the POMC locus, led to the proposal of an association of POMC with human obesity. The dual role of alpha-MSH in regulating food intake and influencing hair pigmentation predicts that the phenotype associated with a defect in POMC function would include obesity, alteration in pigmentation and ACTH deficiency. The observation of these symptoms in two probands prompted us to search for mutations within their POMC genes. Patient 1 was found to be a compound heterozygote for two mutations in exon 3 (G7013T, C7133delta) which interfere with appropriate synthesis of ACTH and alpha-MSH. Patient 2 was homozygous for a mutation in exon 2 (C3804A) which abolishes POMC translation. These findings represent the first examples of a genetic defect within the POMC gene and define a new monogenic endocrine disorder resulting in early-onset obesity, adrenal insufficiency and red hair pigmentation.

LMNA, encoding lamin A/C, is mutated in partial lipodystrophy.

The lipodystrophies are a group of disorders characterized by the absence or reduction of subcutaneous adipose tissue. Partial lipodystrophy (PLD; MIM 151660) is an inherited condition in which a regional (trunk and limbs) loss of fat occurs during the peri-pubertal phase. Additionally, variable degrees of resistance to insulin action, together with a hyperlipidaemic state, may occur and simulate the metabolic features commonly associated with predisposition to atherosclerotic disease. The PLD locus has been mapped to chromosome 1q with no evidence of genetic heterogeneity. We, and others, have refined the location to a 5.3-cM interval between markers D1S305 and D1S1600 (refs 5, 6). Through a positional cloning approach we have identified five different missense mutations in LMNA among ten kindreds and three individuals with PLD. The protein product of LMNA is lamin A/C, which is a component of the nuclear envelope. Heterozygous mutations in LMNA have recently been identified in kindreds with the variant form of muscular dystrophy (MD) known as autosomal dominant Emery-Dreifuss MD (EDMD-AD; ref. 7) and dilated cardiomyopathy and conduction-system disease (CMD1A). As LMNA is ubiquitously expressed, the finding of site-specific amino acid substitutions in PLD, EDMD-AD and CMD1A reveals distinct functional domains of the lamin A/C protein required for the maintenance and integrity of different cell types.

[Delayed effects of oncological therapy]. / Spätfolgen onkologischer Therapie.

Due to therapy-associated improvements in survival rates, delayed effects of cancer are a rapidly increasing but as yet only poorly recognized problem. These delayed sequelae, which by definition occur years after the primary disease, include secondary tumors and many non-oncological internal medical problems. Little attention has so far been paid to the cardiovascular, gastrointestinal, renal and endocrinal delayed side effects and must be specifically addressed due to the often slowly progressing symptoms.

Variation of the baseline characteristics and treatment parameters over time: an analysis of 15 years of growth hormone replacement in adults in the German KIMS database.

The purpose of this study is to examine potential implications of changes in the approach to adult growth hormone (GH) replacement (GHR) over the last 15 years. Therefore, we analysed the German KIMS database as one of the largest single country pharmacoepidemiological databases on adult GH deficiency (GHD). Based on the date of their first GH application patients were assigned to three intervals (1995-1999, 2000-2004, 2005-2009). A multivariate analysis of variance with interval and sex as independent variables was conducted. Differences were analysed with respect to IGF-I standard deviation score (SDS), quality of life, latency between GHD diagnosis and first GH dose, body mass index, waist-hip ratio, lipid profile, and GH dose. All analyses were conducted at baseline, 1 year, and 3 years of GHR. We detected significant associations between time interval and patient characteristics at baseline and with treatment effects. Recently, patients with less severe GHD (mean IGF-I SDS: -2.1, -1.6, -1.0 in the 1st, 2nd and 3rd interval; p = 0.000) are treated with lower GH starting doses (mean 0.30, 0.19, 0.21 mg/day in the 1st, 2nd and 3rd interval; p = 0.000). In the first time interval, IGF-I SDS was not normalized in females after 3 years of GHR. The results of our analysis demonstrate prominent changes in patient characteristics and handling of GHR. They highlight that approach to therapy and patient inclusion criteria change over time and may represent an important confounder for any analysis in epidemiological surveillance surveys.

[Ectopic hormone secretion by neuroendocrine tumors]. / Ektope Hormonsekretion bei neuroendokrinen Tumoren.

Ectopic hormone production is a rare complication in neuroendocrine tumors. Tumors producing corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) are most commonly observed, leading to the classical symptoms of Cushing's syndrome. Additionally, a very low percentage of neuroendocrine tumors can produce growth hormone-releasing hormone (GHRH) leading to classical features of acromegaly. Moreover, ectopic antidiuretic hormone (ADH) secretion has been described in neuroendocrine tumors presenting as hyponatremia due to the syndrome of inappropriate ADH secretion. Other ectopic hormone secretions, such as paraneoplastic gonadotropin release are rarely observed. Ectopic hormone secretion is not usually associated with a detectable pituitary mass and diagnosis is based on the measurement of circulating peptides. This is frequently assisted by imaging techniques, such as somatostatin receptor scintigraphy. Therapeutically a curative approach is the primary goal but in advanced tumors palliative treatment aims to control symptoms with the help of specific antihormonal compounds, such as somatostatin analogues.

Malignancy rates in thyroid nodules: a long-term cohort study of 17,592 patients.

Objectives: Ultrasound diagnosis of thyroid nodules has greatly increased their detection rate. Their risk for malignancy is estimated between 7 and 15% in data from specialized centers which are used for guidelines recommendations. This high rate causes considerable anxiety to patients upon first diagnosis. Here, we retrospectively analyzed the malignancy rate of sonographically diagnosed nodules larger than 1 cm from a primary/secondary care center when long-term longitudinal follow-up was included. Patients/methods: In the study, 17,592 patients were diagnosed with a thyroid nodule larger than 1 cm, of whom 7776 were assessed by fine-needle aspiration cytology (FNAC) and 9816 by sonography alone. 9568 patients were initially discharged due to innocent results of FNAC and/or ultrasound. In 1904 patients, definitive histology was obtained, and 6731 cases were included in the long-term follow-up (up to 23 years, median 5 years). Results: Malignancy was histologically confirmed in 189 patients (1.1% of all) when excluding accidentally diagnosed papillary microcarcinomas. 155 were diagnosed during the first year of management, 25 in years 2-5 of follow-up, 9 in years 6-10 and nil in 1165 patients followed beyond 10 years. Conclusions: The malignancy rate of thyroid nodules from primary/secondary care was much lower than that previously reported. During follow-up for more than 5 years, their rate rapidly dropped to less than 1/1000 cases. This low malignancy rate may help to reassure patients first confronted with the diagnosis of a thyroid nodule, substantially reduce their anxiety and avoid unwarranted diagnostic and therapeutic procedures.

[Neuroendocrine disturbances after acquired brain damage]. / Hormonstörungen nach erworbener Hirnschädigung.

Hypopituitarism is not a rare disease and its clinical signs and symptoms deserve the attention of the clinically practising neurologist. Next to the classical cause of hypopituitarism mediated by tumours of the hypothalamo-pituitary region, a number of recent articles have highlighted the high frequency of central endocrine disturbances in patients with brain damage, i. e. not only after traumatic brain injury and subarachnoid haemorrhage but also as a consequence of the treatment of childhood brain tumours. This article provides an overview of the clinical symptomatology and pathophysiology of hypopituitarism as well as the current knowledge about neuroendocrine disturbances in the adult patient suffering from the above-mentioned disorders.

Following brain trauma, copeptin, a stable peptide derived from the AVP precusor, does not reflect osmoregulation but correlates with injury severity.

The incidence of water and electrolyte disturbances following traumatic brain injury (TBI) is considerable and has been attributed to a dysregulation of the hypothalamic peptide arginine-vasopressin (AVP). Copeptin, the C-terminal part of the AVP prohormone, reflects AVP activity. In 71 TBI patients we measured copeptin in serum by a sandwich immunoassay. Injury severity was assessed by Glasgow Coma Score (GCS) and computed tomography, and recovery by Glasgow Outcome Score (GOS). Neuroendocrine and osmoregulation regulation were examined on day 0, 3 and 7, and 24 months post-injury. Copeptin was highest on admission (40.0 +/- 72.3 pmol/l), stabilized on day 3 and 7 (21.2 +/- 18.3 resp. 20.3 +/- 17.1 pmol/l), and normalized at follow-up (4.2 +/- 1.7 pmol/l). On admission, there was a correlation between serum sodium and urine excretion (p = 0.003), but the correlation got lost on day 3 and 7. Copeptin did not reflect the individual 24 h urine excretion or serum sodium levels indicating an uncoupling of copeptin/AVP release and renal water excretion. High copeptin level on day 3 were correlated with a low GCS (p < 0.001), midline shift (p = 0.019), intracerebral hemorrhage (p = 0.026), SAPS score (p = 0.001), as well as with a low GOS (p = 0.031). Copeptin was significantly decreased following skullbase fracture (p = 0.016).Our data reveal a loss of hypothalamic osmoregulation following TBI. The measurement of Copeptin/AVP release reveals a significant predictive function for the severity of TBI.

[Synthesis, metabolism and diagnostics of thyroid hormones]. / Synthese, Stoffwechsel und Diagnostik der Schilddrüsenhormone.

Understanding of biosynthesis and metabolism of thyroid hormones have recently been substantially improved via the molecular characterization of key players like proteins essential for hormone biosynthesis, cellular thyroid hormone transporters, and intracellular enzymes involved in their activation in peripheral tissues. This improved our understanding of a number of difficult to interpret laboratory conditions. It further stimulated the development of new techniques for the future sensitive and specific measurement of a much wider than the conventional range of secretory products of the thyroid and their organ specific activation.

The cadherin-catenin system: implications for growth and differentiation of endocrine tissues.

Cell-cell adhesion, as mediated by the cadherin-catenin system, is a prerequisite for normal cell function and the preservation of tissue integrity. With recent progress in our understanding, beta-catenin as a component of a complex signal transduction pathway may serve as a common switch in central processes that regulate cellular differentiation and growth. The function of the cadherin-catenin system in cell adhesion as well as in intracellular signaling, appears to be subjected to multifactorial control by a variety of different mechanisms, and data on a hormonal control of these signaling pathways, even though scarce to date, suggest an important regulatory influence in many cellular systems. Loss of E-cadherin-catenin function was described in many tumors along with an increased invasiveness and a decreased prognosis of many carcinomas, including tumors of endocrine glands and their target systems, and a causal role of this loss-of-function in the multifactorial process of tumorigenesis was recently proven in genetic mouse models. Modification of E-caderin-catenin function in endocrine and nonendocrine tumors may involve germline and somatic gene mutations, epigenetic mechanisms such as gene silencing due to promotor-hypermethylation, and posttranscriptional events, likely to be involved in many endocrine tissues and their target organs. Such events may converge on nuclear activation of oncogenes such as c-myc by the beta-catenin/TCF4 complex. The expression and functional status of the components of the cadherin-catenin system may serve as prognostic markers for endocrine and nonendocrine tumors. The frequent involvement of functional dysregulation in many tumors raises hopes that better definition of the regulation of all components of the cadherin-catenin system and their response to extracellular modulators may eventually lead to new therapeutic approaches for these tumors and help to prevent, more specifically, growth, invasion, and metastasis of these carcinomas.

Serum leptin and ghrelin correlate with disease activity in ANCA-associated vasculitis.

OBJECTIVES: To study serum levels of leptin and ghrelin in ANCA-associated vasculitis (AAV). METHODS: Thirty-seven patients with AAV (21 patients with active AAV at initial presentation and during follow-up, 16 patients with AAV in long-term remission) and 21 matched healthy controls were included. Serum levels of leptin and ghrelin were measured at 0, 6 and 12 months by radioimmunoassay. Disease activity was gauged by Birmingham Vasculitis Activity Score (BVAS), CRP and circulating endothelial cells (CECs). RESULTS: Leptin levels were significantly lower in patients than in healthy controls (9.1 +/- 6.1 vs 22.3 +/- 22.4 ng/ml; P < 0.05). The difference persisted when corrected for BMI. Leptin levels increased significantly after 6 (27.8 +/- 21.9 ng/ml; P < 0.001) and 12 months (24.6 +/- 21.0 ng/ml; P < 0.001). Ghrelin levels were significantly elevated in patients compared with controls (402.6 +/- 112.9 vs 294.8 +/- 70.9 pmol/l; P < 0.005) and declined to normal values at 12 months (306.4 +/- 36.2 pmol/l). There was a significant positive correlation between ghrelin levels and disease activity, whereas leptin levels were negatively correlated with disease activity (CRP, BVAS and CECs). Accordingly, correlations between the ghrelin/leptin ratio and markers of disease activity reached the highest level of significance (all P < 0.001). CONCLUSIONS: Active AAV is characterized by decreased serum leptin and increased serum ghrelin, both of which return to normal with successful therapy. The role of leptin and ghrelin during the pathogenesis of AAV and the effects of these peptides on endothelial cells warrant further study.

Assessment of fetal head engagement with transperineal ultrasound: Searching for the cutoff level.

PURPOSE: Engagement of the fetal head is a determinant element when deciding on operative vaginal delivery. In routine practice, engagement is a clinical diagnosis based on transvaginal digital examination. Transperineal ultrasound might provide complementary information useful for measuring the fetal head-perineum distance (HPD). The purpose of this work was to determine the cutoff HPD distinguishing engagement from non-engagement. MATERIALS AND METHODS: This single-center prospective study approved by the institutional review board was conducted between December 25, 2012 and August 31, 2015 in 411 nulliparous women; 20 did not provide informed consent and were excluded; analysis concerned 391 patients. Clinical diagnosis - engagement or non-engagement depending on results of the transvaginal digital examination (Farabeuf's and Demelin's signs) - was compared with the ultrasound HPD measurement. RESULTS: The clinical diagnosis was non-engagement at complete dilatation in 96 patients (24.6%). The cutoff HPD distinguishing between engagement and non-engagement was 57mm (AUC 83.5% [95%CI 79.3-87.8]), with 75.0% [65.5-82.6] sensitivity, 75.9% [70.7-80.5] specificity, 50.3% [42.2-58.4] positive predictive value, and 90.3% [86.0-93.4] negative predictive value. CONCLUSIONS: In this series, the HPD cutoff distinguishing between engagement and non-engagement was 57mm. Below this cutoff level, the head should be considered engaged, beyond non-engaged. Nevertheless, the pertinence of this cutoff level is hampered by the imprecision of the gold standard used for the clinical diagnosis (transvaginal digital examination). In case of doubt, we recommend, in addition to considering the obstetrical setting, to combine transperineal ultrasound with transvaginal digital examination to avoid deleterious failure of operative vaginal delivery.

Time series prediction of plasma hormone concentration. Evidence for differences in predictability of parathyroid hormone secretion between osteoporotic patients and normal controls.

Recent evidence links osteoporosis, a disease of bone remodeling, to changes in the dynamics of parathyroid hormone secretion. We use nonlinear and linear time series prediction to characterize the secretory dynamics of parathyroid hormone in both healthy human subjects and patients with osteoporosis. Osteoporotic patients appear to lack the periods of high predictability found in normal humans. Our results may provide an explanation for why an intermittent administration of parathyroid hormone is effective in restoring bone mass in osteoporotic patients.

Nitric oxide may mediate the hemodynamic effects of recombinant growth hormone in patients with acquired growth hormone deficiency. A double-blind, placebo-controlled study.

We studied the effects of recombinant growth hormone on systemic nitric oxide (NO) formation and hemodynamics in a double-blind, placebo-controlled trial in adult patients with acquired growth hormone deficiency. 30 patients were randomly allocated to either recombinant human growth hormone (r-hGH; 2.0 IU/d) or placebo for 12 mo. In the subsequent 12 mo, the study was continued with both groups of patients receiving r-hGH. In months 1, 3, 6, 9, and 12 of each year, urine and plasma samples were collected for the determination of urinary nitrate and cyclic GMP as indices of systemic NO production, and of plasma IGF-1 levels. Cardiac output was measured in months 1, 12, and 24 by echocardiography. r-hGH induced a fourfold increase in plasma IGF-1 concentrations within the first month of treatment. Urinary nitrate and cyclic GMP excretion rates were low at baseline in growth hormone-deficient patients (nitrate, 96.8+/-7.4 micromol/mmol creatinine; cyclic GMP, 63.6+/-7.1 nmol/mmol creatinine) as compared with healthy controls (nitrate, 167.3+/-7.5 micromol/mmol creatinine; cyclic GMP, 155.2+/-6.9 nmol/mmol creatinine). These indices of NO production were significantly increased by r-hGH, within the first 12 mo in the GH group, and within the second 12 mo in the placebo group. While systolic and diastolic blood pressure were not significantly altered by r-hGH, cardiac output significantly increased by 30-40%, and total peripheral resistance decreased by approximately 30% in both groups when they were assigned to r-hGH treatment. In the second study year, when both groups were given r-hGH, there were no significant differences in plasma IGF-1, urinary nitrate, or cyclic GMP excretion, or hemodynamic parameters between both groups. In conclusion, systemic NO formation is decreased in untreated growth hormone-deficient patients. Treatment with recombinant human growth hormone normalizes urinary nitrate and cyclic GMP excretion, possibly via IGF-1 stimulation of endothelial NO formation, and concomitantly decreases peripheral arterial resistance. Increased NO formation may be one reason for improved cardiovascular performance of patients with acquired hypopituitarism during growth hormone therapy.

Distinct roles of free leptin, bound leptin and soluble leptin receptor during the metabolic-inflammatory response in patients with liver cirrhosis.

BACKGROUND: Alteration of the leptin system appears to play a role in the inflammatory-metabolic response in catabolic diseases such as chronic liver diseases. AIM: To investigate the association between leptin components, inflammatory markers and hepatic energy and substrate metabolism. METHODS: We investigated in vivo hepatic substrate and leptin metabolism in 40 patients employing a combination of arterial and hepatic vein catheterization techniques and hepatic blood flow measurements. In addition to metabolic, inflammatory and neuroendocrine parameters, circulating levels of free leptin, bound leptin and soluble leptin receptor were determined. RESULTS: Compared with controls, bound leptin and soluble leptin receptor levels were significantly elevated in cirrhosis, while free leptin did not increase. In cirrhosis bound leptin was correlated with soluble leptin receptor (r = 0.70, P < 0.001). Free leptin was positively correlated with metabolic parameters such as energy storage (body fat mass; r = 0.36, P < 0.05), insulin and insulin resistance (r = 0.48; r = 0.46, P < 0.01) as well as with hepatic glucose and energy release (r = 0.35 and r = 0.40, P < 0.05). In contrast, bound leptin and soluble leptin receptor were linked to proinflammatory cytokines and sympathetic activity (r = 0.61 and r = 0.56, P < 0.01). CONCLUSION: The components of the leptin system (free leptin, bound leptin and soluble leptin receptor) have distinct roles in metabolic and inflammatory processes in patients with liver cirrhosis. The better understanding of this metabolic and inflammatory tissue-repair response may lead to innovative new therapeutic strategies in liver disease as well as in various other catabolic diseases.

Mild Thyrotoxicosis Leads to Brain Perfusion Changes: An Arterial Spin Labelling Study.

Hypo- and hyperthyroidism have effects on brain structure and function, as well as cognitive processes, including memory. However, little is known about the influence of thyroid hormones on brain perfusion and the relationship of such perfusion changes with cognition. The present study aimed to demonstrate the effect of short-term experimental hyperthyroidism on brain perfusion in healthy volunteers and to assess whether perfusion changes, if present, are related to cognitive performance. It is known that an interaction exists between brain perfusion and cerebral oxygen consumption rate and it is considered that neural activation increases cerebral regional perfusion rate in brain areas associated with memory. Measuring cerebral blood flow may therefore represent a proxy for neural activity. Therefore, arterial spin labelling (ASL) measurements were conducted and later analysed to evaluate brain perfusion in 29 healthy men before and after ingesting thyroid hormones for 8 weeks. Psychological tests concerning memory were performed at the same time-points and the results were correlated with the imaging results. In the hyperthyroid condition, perfusion was increased in the posterior cerebellum in regions connected with cerebral networks associated with cognitive control and the visual cortex compared to the euthyroid condition. In addition, these perfusion changes were positively correlated with changes of performance in the German version of the Auditory Verbal Learning Task [AVLT, Verbaler Lern-und-Merkfähigkeits-Test (VLMT)]. Cerebellar perfusion and function therefore appears to be modulated by thyroid hormones, likely because the cerebellum hosts a high number of thyroid hormone receptors.