Pituitary hypophysitis in granulomatosis with polyangiitis (GPA): a case series.

Granulomatosis with polyangiitis (GPA) rarely involves the pituitary gland. Pituitary involvement has been reported in ~ 1% of all cases of GPA. Most commonly, pituitary swelling and inflammation results in symptoms due to pituitary mass effect and arginine vasopressin deficiency. To date, there are no pituitary-specific treatment guidelines for this rare condition. We present three patients with GPA-related hypophysitis highlighting the spectrum of pituitary involvement. All three patients were successfully treated with immunosuppressive regimens that included rituximab (RTX). Following remission induction with high-dose glucocorticoids, patients received 6 monthly RTX for remission maintenance. RTX was well tolerated without significant side effects.

Interpretation of Serum Gonadotropin Levels in Hyperprolactinaemia.

BACKGROUND/AIMS: Hyperprolactinaemia is a common cause of amenorrhoea due to hypogonadotropic hypogonadism. Prolactin is hypothesised to impede the reproductive axis through an inhibitory action at the hypothalamus. However, limited data exist to aid the interpretation of serum gonadotropins in the context of hyperprolactinaemia. METHODS: Serum gonadotropin values were reviewed in 243 patients with elevated serum monomeric prolactin due to discrete aetiologies at a tertiary reproductive endocrine centre between 2012 and 2015. The cause of hyperprolactinaemia was categorised by an experienced endocrinologist/pituitary multidisciplinary team, unless superseded by histology. The most frequently encountered diagnoses were microprolactinoma (n = 88), macroprolactinoma (n = 46), non-functioning pituitary adenoma (NFPA) (n = 72), drug-induced hyperprolactinaemia (n = 22) and polycystic ovarian syndrome (PCOS) (n = 15). RESULTS: In patients with prolactinoma and modestly raised serum prolactin levels (< 4,000 mU/L), increasingly FSH-predominant gonadotropin values were observed with rising prolactin level, consistent with a progressive reduction in hypothalamic gonadotropin-releasing hormone (GnRH) pulsatility. Patients with prolactinoma and higher prolactin values (> 4,000 mU/L) were more likely to have a reduction in serum levels of both FSH and LH, consistent with direct pituitary gonadotrope dysfunction. Patients with macroadenoma and extremes of serum gonadotropin values (either serum FSH or LH > 8 IU/L) were more likely to have NFPA than prolactinoma. Patients with PCOS and hyperprolactinaemia had LH-predominant secretion in keeping with increased GnRH pulsatility despite a raised prolactin level. CONCLUSION: The pattern of gonadotropin secretion in patients with hyperprolactinaemia reflects the underlying aetiology.

Clinical outcomes in patients with nonfunctioning pituitary adenomas managed conservatively.

CONTEXT: The natural history and the optimum management of patients with nonfunctioning pituitary adenomas (NFPAs) are unclear. OBJECTIVE: Our objective was to characterize the natural history of patients with NFPAs managed conservatively. DESIGN AND PATIENTS: We conducted a retrospective analysis of patients presenting to a tertiary referral centre between 1986 and 2009. Patients with pituitary adenomas and no clinical or biochemical evidence of hormonal hypersecretion were included. Those presenting with apoplexy or a radiological follow-up period of less than 1 year were excluded. The pituitary imaging for all patients was re-examined by two neuroradiologists in consensus. OUTCOME MEASURES: The outcome measures were change in tumour size and pituitary hormone function. RESULTS: Sixty-six patients were managed conservatively for a mean follow-up period of 4·3 years (range: 1-14·7). Forty-seven (71%) had a macroadenoma, and nineteen (29%) had a microadenoma. Tumour size decreased or remained stable in 40% of macroadenomas and 47% of microadenomas. The median annual growth rate of enlarging macroadenomas and microadenomas was 1·0 mm/year and 0·4 mm/year, respectively. The median annual growth rate of macroadenomas was significantly higher than that of microadenomas (P < 0·01). Sixty-eight percentage of patients with a macroadenoma had pituitary hormone deficiency in one or more axes, compared to 42% of those with a microadenoma. CONCLUSION: Patients with NFPAs without optic chiasm compression can be managed conservatively. All patients need pituitary function assessment, irrespective of tumour size. These findings provide clinically relevant data for the management of patients with NFPAs.

Effects of immune checkpoint inhibitor associated endocrinopathies on cancer survival.

Objectives: Immune checkpoint inhibitors (ICIs) are associated with immune-related adverse events (irAEs), of which endocrinopathies are common. We characterized endocrine and non-endocrine irAEs in cancer patients receiving ICIs, identified risk factors for their development and established whether endocrine and non-endocrine irAEs were differentially associated with improved cancer prognosis. Design and methods: Single-center, retrospective cohort study of patients with advanced or metastatic solid tumors receiving at least one ICI treatment cycle (242 men, 151 women, median age 65 years). Main outcome measures were incidence of any irAE during the study period, overall survival and time to treatment failure. Results: Non-endocrine irAEs occurred in 32% and endocrine irAEs in 12% of patients. Primary thyroid dysfunction was the most common endocrine irAE (9.5%) and the majority of endocrinopathies required permanent hormone replacement. Women had an increased risk of developing endocrine irAEs (p = 0.017). The biggest survival advantage occurred in patients who developed both endocrine and non-endocrine irAEs (overall survival: HR 0.16, CI 0.09-0.28). Time to treatment failure was also significantly improved in patients who developed endocrine irAEs (HR 0.49, CI 0.34 - 0.71) or both (HR 0.41, CI 0.25 - 0.64) but not in those who only developed non-endocrine irAEs. Conclusions: Women may have increased risk of endocrine irAEs secondary to ICI treatment. This is the first study to compare the effects of endocrine irAEs with non-endocrine irAEs on survival. Development of endocrine irAEs may confer survival benefit in ICI treatment and future, prospective studies are needed to elucidate this.

Comparison of the overnight metyrapone and glucagon stimulation tests in the assessment of secondary hypoadrenalism.

OBJECTIVE: The insulin tolerance test (ITT) is contraindicated in a proportion of patients with suspected ACTH deficiency. The aim of this study was to investigate the diagnostic accuracy of the glucagon stress test (GST) compared with the overnight metyrapone test (OMT) in patients with contraindications to ITT. DESIGN: This was a prospective comparison of the GST to the OMT in patients with suspected ACTH deficiency and contraindications to the ITT. The OMT was used as the standard for comparison. The study was conducted at two tertiary referral centres for pituitary disease. PATIENTS: Seventy-eight patients underwent contemporaneous OMT and GST of whom 61 had sufficient suppression of cortisol during the OMT to be included in the comparison. Forty had suffered traumatic brain injury, 36 had organic pituitary disorders and two were classified as 'other'. MEASUREMENTS: ACTH sufficiency was defined as 0800h 11-deoxycortisol ≥ 200 nmol/l on OMT and peak cortisol ≥ 440 nmol/l on GST, as per local reference ranges. RESULTS: There was significant discrepancy between the proportion of patients diagnosed with ACTH deficiency using the OMT (39%) and GST (89%). From our data, a GST peak cortisol cut-off of ≥350 nm provides the combination of optimal sensitivity (71%) and specificity (57%), compared with a higher sensitivity (88%) but poor specificity (11%) using a cut-off of ≥440 nm. CONCLUSIONS: The GST should be used with caution as a diagnostic test of ACTH reserve. The OMT should be used in preference to the GST to assess the hypothalamic pituitary adrenal axis where ITT is contraindicated.

Adjuvant lithium improves the efficacy of radioactive iodine treatment in Graves' and toxic nodular disease.

CONTEXT: Lithium increases iodine retention in the thyroid gland and inhibits thyroid hormone release. Although lithium has been reported to improve the efficacy of radioactive iodine (RAI) treatment in Graves' disease, its role as an adjunct to RAI treatment of hyperthyroidism, particularly in toxic nodular disease, remains contentious. OBJECTIVE: To assess whether adjuvant lithium increases the efficacy of a fixed dose RAI regimen in Graves' and toxic nodular hyperthyroid patients. DESIGN AND SETTING: Retrospective cohort study in a tertiary referral centre. Two hundred and four hyperthyroid patients (163 Graves' disease, 26 toxic multinodular goitre and 15 solitary toxic thyroid adenoma). INTERVENTION: One hundred and three patients received RAI alone (median dose 558 MBq). One hundred and one patients received RAI (median dose 571 MBq) with adjuvant lithium (800 mg/day for 10 days). MAIN OUTCOME MEASURE: Proportion of patients cured at any time over a 1-year period following RAI treatment. Cure was defined as sustained (two or more sequential time points) biochemical euthyroidism or hypothyroidism during the follow-up period. RESULTS: The likelihood of cure at any time was 60% greater in all hyperthyroid patients (Graves' plus toxic nodular disease) receiving adjuvant lithium (n = 204, P = 0·003). In patients with Graves' disease receiving RAI + lithium, there was a similar occurrence in cure (n = 163, P = 0·006). Cure was twice as likely in patients with toxic nodular (non-Graves') disease receiving RAI + lithium compared with RAI alone (n = 41, P = 0·01). CONCLUSIONS: This study supports the use of adjuvant lithium to improve the efficacy of RAI in the treatment of Grave's disease and suggests a novel role in the management of toxic nodular (non-Graves') disease.

Improved diagnostic accuracy for neuroendocrine neoplasms using two chromogranin A assays.

CONTEXT: Chromogranin A (Cg A) is the best available diagnostic marker for neuroendocrine neoplasms (NENs). However, clinical interpretation of Cg A results may be limited by considerable heterogeneity between commonly available Cg A assays. Variation in diagnostic accuracy of these assays largely reflects differences in antibody specificities. We compared the diagnostic utility of four Cg A assays [Imperial Supra-regional Assay Service radioimmunoassay (SAS) and three commercial assays, Cisbio, DAKO and Eurodiagnostica]. METHOD: Plasma Cg A was measured using these four assays in 125 patients with NENs, 41 patients with cancers other than NENs and 108 healthy controls. RESULT: There was no significant difference in diagnostic accuracy between any of the four assays alone and no single assay positively identified all patients with NEN. However, concordance between assays was variable. Cisbio and SAS assays were least concordant. We, therefore, hypothesized that using a combination of the least concordant Cg A assays will improve NEN diagnosis by detecting a larger number of Cg A epitopes and hence patients with NEN. Consistent with our hypothesis, multiple logistic regression analysis showed that the combination of Cisbio and SAS assays was more useful than any other combinations or any assay alone in predicting a NEN diagnosis. CONCLUSION: Although individually, all four Cg A assays are similarly useful for the measurement of Cg A in the diagnosis of a NEN, in patients with a suspected NEN, negative results by one assay should prompt analysis by a second assay. The combination of Cisbio and SAS assays may have greatest diagnostic utility.

Effectiveness of short, personalised student assistantships: an evaluative study across eight London hospitals.

OBJECTIVES: Student assistantships are recommended to prepare medical graduates for clinical practice. Traditionally, assistantships have consisted of longer placements, often up to 15 weeks. However, within the constraints of the final year, medical schools need to carefully balance the time required for specialty placements, assessments and the risk of student burnout. We set out to evaluate the effectiveness of shorter, personalised student assistantships. DESIGN: An evaluative study on the changes in final year student confidence in preparedness for practice after a 3-week assistantship with defined learning objectives and learning needs assessment. SETTING: Eight hospitals affiliated with Imperial College School of Medicine. OUTCOMES: Student confidence in 10 learning outcomes including organising ward rounds, documentation, communication with colleagues, communication with patients and relatives, patient handover, practical procedures, patient management, acute care, prioritisation and out-of-hours clinical work. RESULTS: Two hundred and twenty final year medical students took part in the student assistantship, of whom 208 completed both the pre-assistantship and post-assistantship confidence rating questionnaires (95% completion rate). After the assistantship, 169 (81%) students expressed increased confidence levels in one or more learning objectives. For each individual learning objective, there was a significant change in the proportion of students who agreed or strongly agreed after the assistantship (p<0.0001). CONCLUSION: Overall, the focused 3-week, personalised student assistantships led to significant improvement across all learning objectives related to preparedness for practice. The use of the pre-assistantship confidence rating questionnaire allowed students to identify and target areas of learning needs during their assistantship.

Late-night salivary cortisol and cortisone should be the initial screening test for Cushing's syndrome.

Endogenous Cushing's syndrome (CS) poses considerable diagnostic challenges. Although late-night salivary cortisol (LNSC) is recommended as a first-line screening investigation, it remains the least widely used test in many countries. The combined measurement of LNSC and late-night salivary cortisone (LNS cortisone) has shown to further improve diagnostic accuracy. We present a retrospective study in a tertiary referral centre comparing LNSC, LNS cortisone, overnight dexamethasone suppression test, low-dose dexamethasone suppression test and 24-h urinary free cortisol results of patients investigated for CS. Patients were categorised into those who had CS (21 patients) and those who did not (33 patients). LNSC had a sensitivity of 95% and a specificity of 91%. LNS cortisone had a specificity of 100% and a sensitivity of 86%. With an optimal cut-off for LNS cortisone of >14.5 nmol/L the sensitivity was 95.2%, and the specificity was 100% with an area under the curve of 0.997, for diagnosing CS. Saliva collection is non-invasive and can be carried out at home. We therefore advocate simultaneous measurement of LNSC and LNS cortisone as the first-line screening test to evaluate patients with suspected CS.

Assessment of cardiac valve dysfunction in patients receiving cabergoline treatment for hyperprolactinaemia.

OBJECTIVE: Cabergoline is a highly effective medical treatment for patients with hyperprolactinaemia. There is an increased risk of valvular heart disease in patients receiving cabergoline for Parkinson's disease. This study examined whether cabergoline treatment of hyperprolactinaemia is associated with a greater prevalence of valvulopathy. DESIGN: Cross-sectional, two-dimensional echocardiographic study performed by a single echocardiographer. PATIENTS: Seventy-two patients (median age 36 years, 19 men) receiving cabergoline for hyperprolactinaemia, and 72 controls prospectively matched for age, sex and cardiovascular risk factors. Measurements Assessment of valvular mobility, regurgitation and morphology. RESULTS: Median cumulative dose exposure for cabergoline was 126 (58-258) mg, and patients had received cabergoline for 53 (26-96) months. The frequency of mild mitral regurgitation was identical (5/72, 7%) in patient and control groups. Mild aortic regurgitation was not significantly different between groups (4/72 [controls] vs 2/72 [patients], P = 0.681). There was only one case of tricuspid regurgitation, which was mild and observed in a cabergoline-treated patient. Nodular thickening of the right coronary cusp, noncoronary cusp or left coronary cusp of the aortic valve was observed at a similar frequency in both groups. There were no cases of extensive thickening of any valvular leaflet. CONCLUSION: Our data demonstrates that there is no association between cabergoline treatment for hyperprolactinaemia and valvulopathy. This study therefore supports continued use of low-dose cabergoline for patients with hyperprolactinaemia.

Outcomes of Patients with Nelson's Syndrome after Primary Treatment: A Multicenter Study from 13 UK Pituitary Centers.

CONTEXT: Long-term outcomes of patients with Nelson's syndrome (NS) have been poorly explored, especially in the modern era. OBJECTIVE: To elucidate tumor control rates, effectiveness of various treatments, and markers of prognostic relevance in patients with NS. PATIENTS, DESIGN, AND SETTING: Retrospective cohort study of 68 patients from 13 UK pituitary centers with median imaging follow-up of 13 years (range 1-45) since NS diagnosis. RESULTS: Management of Cushing's disease (CD) prior to NS diagnosis included surgery+adrenalectomy (n = 30; eight patients had 2 and one had 3 pituitary operations), surgery+radiotherapy+adrenalectomy (n = 17; two received >1 courses of irradiation, two had ≥2 pituitary surgeries), radiotherapy+adrenalectomy (n = 2), and adrenalectomy (n = 19). Primary management of NS mainly included surgery, radiotherapy, surgery+radiotherapy, and observation; 10-year tumor progression-free survival was 62% (surgery 80%, radiotherapy 52%, surgery+radiotherapy 81%, observation 51%). Sex, age at CD or NS diagnosis, size of adenoma (micro-/macroadenoma) at CD diagnosis, presence of pituitary tumor on imaging prior adrenalectomy, and mode of NS primary management were not predictors of tumor progression. Mode of management of CD before NS diagnosis was a significant factor predicting progression, with the group treated by surgery+radiotherapy+adrenalectomy for their CD showing the highest risk (hazard ratio 4.6; 95% confidence interval, 1.6-13.5). During follow-up, 3% of patients had malignant transformation with spinal metastases and 4% died of aggressively enlarging tumor. CONCLUSIONS: At 10 years follow-up, 38% of the patients diagnosed with NS showed progression of their corticotroph tumor. Complexity of treatments for the CD prior to NS diagnosis, possibly reflecting corticotroph adenoma aggressiveness, predicts long-term tumor prognosis.

Day 5 morning serum cortisol predicts hypothalamic-pituitary-adrenal function after transsphenoidal surgery for pituitary tumors.

BACKGROUND: Adrenal insufficiency is a complication of transsphenoidal surgery (TSS) for pituitary adenoma, and correct identification of patients requiring glucocorticoid replacement is important. Controversy exists over which early postoperative 9 AM cortisol concentration reliably predicts hypothalamic-pituitary-adrenal (HPA) axis reserve, as defined by the insulin tolerance test (ITT). METHODS: Data were reviewed for 36 patients undergoing TSS followed by day 5 postoperative 9 AM cortisol measurement and ITT 6 weeks postsurgery. All patients received postoperative glucocorticoid replacement, which was discontinued if the 9 AM serum cortisol was >300 nmol/L. RESULTS: Of 23 patients who failed the ITT (peak cortisol <500 nmol/L), 20 also had a day 5, 9 AM serum cortisol <300 nmol/L. Nine of 13 patients who passed the ITT had a day 5, 9 AM cortisol >300 nmol/L. The cutoff cortisol concentration of 300 nmol/L had 86.9% (66.4%-97.2%) diagnostic sensitivity, 69.2% (38.6%-90.9%) diagnostic specificity, and 83.3% (61.8%-94.5%) positive predictive value (PPV) for detecting secondary adrenal insufficiency. Increasing the cutoff to 392 nmol/L resulted in 100% (85.2%-100%) sensitivity, 46.1% (19.2%-74.9%) specificity, and 76.6% (57.3%-89.4%) PPV. Decreasing the cutoff to 111 nmol/L resulted in 100% (75.3%-100%) specificity and 100% (67.9%-100%) PPV, although sensitivity was 47.8% (26.8%-69.4%). CONCLUSIONS: A day 5 post-TSS 9 AM serum cortisol <111 nmol/L reliably detects secondary adrenal insufficiency, and concentrations >392 nmol/L support intact HPA function. Because concentrations of 111-392 nmol/L are poorly predictive of HPA function, glucocorticoid replacement should continue in such cases until definitive testing is performed using an ITT.

The McKittrick-Wheelock syndrome: a case of acute renal failure due to neoplastic cholera.

The McKittrick-Wheelock syndrome is characterized by severe electrolyte and fluid depletion as a result of rectal tumor hypersecretion. Typically, a metabolic acidosis ensues. We report the case of a 58-year-old man who presented with a mixed metabolic acidosis and alkalosis. He was hyponatremic, hypokalemic, and hypochloremic, with acute renal failure on blood testing. Following fluid resuscitation, a predominant alkalemia was observed. The patient was found to be passing 1.5 L of mucous per rectum per day, containing high concentrations of sodium and potassium, similar to that observed in cholera stool. A large rectal villous adenoma was discovered on sigmoidoscopy, and definitive management was achieved by removal of the tumor. This case provides a demonstration of the ranging metabolic disturbance associated with secretory diarrhea. Other endogenous and infective causes are discussed, and mechanisms compared with the case described.

L-Arginine Increases Postprandial Circulating GLP-1 and PYY Levels in Humans.

OBJECTIVE: The satiating effect of protein compared with other nutrients has been well described and is thought to be mediated, in part, by gut hormone release. Previously, it has been shown that oral L-arginine acts as a GLP-1 secretagogue both in vitro and in vivo in rodents. Here, the effect of L-arginine on gut hormone release in humans was investigated. METHODS: The hypothesis was tested in two separate studies. The first study assessed the tolerability of oral L-arginine in healthy human subjects. The second study assessed the effect of oral L-arginine on gut hormone release following an ad libitum meal. Subjects were given L-arginine, glycine (control amino acid), or vehicle control in a randomized double-blind fashion. RESULTS: At a dose of 17.1 mmol, L-arginine was well tolerated and stimulated the release of plasma GLP-1 (P < 0.05) and PYY (P < 0.001) following an ad libitum meal. Food diaries showed a trend toward lower energy intake and particularly fat intake following L-arginine treatment. CONCLUSIONS: L-arginine can significantly elevate GLP-1 and PYY in healthy human volunteers in combination with a meal. Further work is required to investigate whether L-arginine may have utility in the suppression of appetite and food intake.

Clinical and biochemical characteristics of patients presenting with pituitary apoplexy.

PURPOSE: To review the clinical and biochemical characteristics and clinical outcome of patients presenting with pituitary apoplexy to a tertiary centre. METHODS: We retrospectively reviewed the clinical features, predisposing factors, biochemistry and clinical outcome of patients presenting with pituitary apoplexy to Imperial College Healthcare NHS Trust between 1991 to 2015. RESULTS: We identified 64 patients with pituitary apoplexy (more complete clinical records were available in 52 patients). The median age at presentation was 46.7 years (IQR 31.5-57.0 years). Pituitary apoplexy was the first presentation of pituitary disease in 38/52 of patients and predisposing factors were identified in 28/52. Pituitary apoplexy predominantly occurred in patients with non-functioning pituitary adenomas (47/52). Headache was most commonly described as sudden-onset, severe, lateralising to the frontal or temporal regions. Symptoms of meningeal irritation were reported in 7/18 and visual abnormalities in 22/35. A pre-treatment serum cortisol <100nmol/l was recorded in 12/31 of patients. All patients with visual disturbance had some resolution of their visual symptoms whether managed surgically (14/14) or conservatively (5/5), although pituitary endocrine function did not fully recover in any patient. CONCLUSIONS: In conclusion, these data describe the clinical features of pituitary apoplexy to aid the clinician in diagnosing this rare emergency presentation of pituitary disease. Prospective multicentre studies of the presentation of pituitary apoplexy are required to further characterise presentation and outcomes.

Interactions between the melanocortin system and the hypothalamo-pituitary-thyroid axis.

Recent studies of transgenic mice and humans have provided compelling evidence for the importance of the hypothalamic melanocortin system in the regulation of energy balance. Energy homeostasis is a balance between food intake (energy input) and energy expenditure. The melanocortin system regulates feeding via effects of the endogenous agonist, alpha-melanocyte stimulating hormone (alpha-MSH) and the endogenous antagonist agouti-related protein (AGRP) on melanocortin 3 and 4 receptors (MC3-Rs and MC4-Rs). It has been demonstrated that the melanocortin system interacts with the hypothalamo-pituitary-thyroid (HPT) axis. Thyroid hormones influence metabolism and hence energy expenditure. Therefore, an interaction between the HPT axis and the melanocortin system would allow control of both sides of the energy balance equation, by the regulation of both energy input and energy expenditure. Here we will discuss the evidence demonstrating interactions between the melanocortin system and the HPT axis.

A Follow-Up Study of the Prevalence of Valvular Heart Abnormalities in Hyperprolactinemic Patients Treated With Cabergoline.

CONTEXT: Uncertainty exists whether the long-term use of ergot-derived dopamine agonist (DA) drugs for the treatment of hyperprolactinemia may be associated with clinically significant valvular heart disease and whether current regulatory authority guidelines for echocardiographic screening are clinically appropriate. OBJECTIVE: Our objective was to provide follow-up echocardiographic data on a previously described cohort of patients treated with DA for lactotrope pituitary tumors and to explore possible associations between structural and functional valve abnormalities with the cumulative dose of drug used. DESIGN: Follow-up echocardiographic data were collected from a proportion of our previously reported cohort of patients; all had received continuous DA therapy for at least 2 years in the intervening period. Studies were performed according to British Society of Echocardiography minimum standards for adult transthoracic echocardiography. Generalized estimating equations with backward selection were used to determine odds ratios of valvular heart abnormalities according to tertiles of cumulative cabergoline dose, using the lowest tertile as the reference group. SETTING: Thirteen centers of secondary/tertiary endocrine care across the United Kingdom were included. RESULTS: There were 192 patients (81 males; median age, 51 years; interquartile range [IQR], 42-62). Median (IQR) cumulative cabergoline doses at the first and second echocardiograms were 97 mg (20-377) and 232 mg (91-551), respectively. Median (IQR) duration of uninterrupted cabergoline therapy between echocardiograms was 34 months (24-42). No associations were observed between cumulative doses of dopamine agonist used and the age-corrected prevalence of any valvular abnormality. CONCLUSION: This large UK follow-up study does not support a clinically significant association between the use of DA for the treatment of hyperprolactinemia and cardiac valvulopathy.

Triiodothyronine stimulates food intake via the hypothalamic ventromedial nucleus independent of changes in energy expenditure.

Increased food intake is characteristic of hyperthyroidism, although this is presumed to compensate for a state of negative energy balance. However, here we show that the thyroid hormone T(3) directly stimulates feeding at the level of the hypothalamus. Peripheral administration of T(3) doubled food intake in ad libitum-fed rats over 2 h and induced expression of the immediate early gene, early growth response-1, in the hypothalamic ventromedial nucleus (VMN), whereas maintaining plasma-free T(3) levels within the normal range. T(3)-induced feeding occurred without altering energy expenditure or locomotion. Injection of T(3) directly into the VMN produced a 4-fold increase in food intake in the first hour. The majority of T(3) in the brain is reported to be produced by tissue-specific conversion of T(4) to T(3) by the enzyme type 2 iodothyronine deiodinase (D2). Hypothalamic D2 mRNA expression showed a diurnal variation, with a peak in the nocturnal feeding phase. Hypothalamic D2 mRNA levels also increased after a 12- and 24-h fast, suggesting that local production of T(3) may play a role in this T(3) feeding circuit. Thus, we propose a novel hypothalamic feeding circuit in which T(3), from the peripheral circulation or produced by local conversion, stimulates food intake via the VMN.