Copeptin levels are independent of ingested nutrient type after standardised meal administration--the CoMEAL study.

CONTEXT/OBJECTIVE: To clarify ambiguous published data, we determined whether standardized nutrient intake influences serum copeptin concentrations. MATERIALS/METHODS: Thirty healthy volunteers underwent oral glucose tolerance testing (OGTT) and mixed-meal tolerance testing (MMTT), respectively drinking 300 ml/237 ml of glucose-containing or fat/protein/carbohydrate-containing fluid. Copeptin was measured 30 min pre-("baseline")-180 min post-fluid intake. RESULTS: Median [25th-75th percentile] copeptin fell from 4.9 [3.6-8.3]/4.9 [3.6-7.1] pmol/l at OGTT/MMTT baselines to 3.2 (2.8-5.9)/4.1 (2.7-6.1) pmol/l at post-OGTT/post-MMTT nadirs (150 min/120 min; p < 0.001, linear mixed-effect modeling). DISCUSSION/CONCLUSIONS: Regardless of nutrient type ingested, copeptin did not increase, suggesting values can be interpreted independently of prandial status.

Resting Energy Expenditure and Cold-induced Thermogenesis in Patients With Overt Hyperthyroidism.

CONTEXT: Thyroid hormone (TH) is crucial for the adaptation to cold. OBJECTIVE: To evaluate the effect of hyperthyroidism on resting energy expenditure (REE), cold-induced thermogenesis (CIT) and changes in body composition and weight. METHODS: This was a prospective cohort study at the endocrine outpatient clinic of a tertiary referral center. Eighteen patients with overt hyperthyroidism were included. We measured REE during hyperthyroidism, after restoring euthyroid TH levels and after 3 months of normal thyroid function. In 14 of the 18 patients, energy expenditure (EE) was measured before and after a mild cold exposure of 2 hours and CIT was the difference between EEcold and EEwarm. Skin temperatures at 8 positions were recorded during the study visits. Body composition was assessed by dual X-ray absorption. RESULTS: Free thyroxine (fT4) and free triiodothyronine (fT3) decreased significantly over time (fT4, P = .0003; fT3, P = .0001). REE corrected for lean body mass (LBM) decreased from 42 ±â€…6.7 kcal/24 hour/kg LBM in the hyperthyroid to 33 ±â€…4.4 kcal/24 hour/kg LBM (-21%, P < .0001 vs hyperthyroid) in the euthyroid state and 3 months later to 33 ±â€…5.2 kcal/24 hour/kg LBM (-21%, P = .0022 vs hyperthyroid, overall P < .0001). fT4 (P = .0001) and fT3 (P < 0.0001) were predictors of REE. CIT did not change from the hyperthyroid to the euthyroid state (P = .96). Hyperthyroidism led to increased skin temperature at warm ambient conditions but did not alter core body temperature, nor skin temperature after cold exposure. Weight regain and body composition were not influenced by REE and CIT during the hyperthyroid state. CONCLUSION: CIT is not increased in patients with overt hyperthyroidism.

The role of IL-1 in postprandial fatigue.

OBJECTIVES: Cytokines such as IL-1 seems to play a role in the pathogenesis of fatigue associated with some chronic diseases and anti-inflammatory treatment has been shown to reduce these symptoms. Ingestion of a calorie rich meal leads to postprandial fatigue, and is associated with increased systemic concentrations of cytokines, which is more pronounced in obese than lean subjects. We investigated whether postprandial fatigue is regulated by IL-1, and therefore reduced by IL-1 antagonism, in lean and obese subjects. METHODS: In a double-blind, crossover study in 8 lean and 8 obese male subjects, randomized to receive either saline (placebo) or the IL-1 receptor antagonist anakinra, we investigated whether postprandial fatigue was regulated by IL-1. To promote postprandial fatigue, subjects ran 30 min prior to a high-fat, high-carbohydrate meal. Fatigue was determined using the Stanford Sleepiness Scale and blood samples were drawn at baseline and after the intervention. RESULTS: IL-1 antagonism led to a reduction in postprandial fatigue and this effect was more pronounced in obese than lean individuals. CONCLUSIONS: We conclude that IL-1 is involved in the regulation of postprandial fatigue under physiologic conditions in lean and obese individuals. It remains to be shown whether this effect translates into clinical relevant effects.

Copeptin concentrations during psychological stress: the PsyCo study.

OBJECTIVE: The prognostic/diagnostic biomarker copeptin, an arginine vasopressin surrogate, reflects physical stress. Whether copeptin concentration increases upon psychological stress is unknown. We investigated psychological stress effects on copeptin secretion in healthy volunteers and patients with central diabetes insipidus (DI). DESIGN: A prospective observational study was conducted to study the relation between copeptin concentration and psychological stress. METHODS: A total of 20 healthy adults (ten female) and eight patients with central DI (four female) underwent the Trier Social Stress Test including, in order, 30-min waiting period, 10-min anticipation period, 10-min test period and 40-min recovery. Serum copeptin and cortisol concentrations and self-rated stress component feelings were determined in the pre-/post-anticipation period, post-test period and twice post-recovery. RESULTS: In healthy volunteers, the median (25th-75th percentile) copeptin concentration peaked immediately during the post-test period at 5.1 (3.2-7.0) pmol/l, vs 3.7 (2.6-5.4) pmol/l at baseline. Over the measurement course, copeptin concentration significantly elevated (coefficient; 95% CI) (0.14; 0.06-0.23, P=0.002). The important predictors of increase in copeptin concentration were feelings of tension (0.06; 0.04-0.08, P<0.001) and avoidance (0.07; 0.04-0.10; P<0.001). Copeptin and cortisol levels were associated (0.43; 0.13-0.72, P<0.005). Patients with DI had lower baseline concentrations (1.55 (1.2-3.1) pmol/l) when compared with healthy volunteers, P=0.006. Patients with DI showed no increase upon psychological stress (peak 2.15 pmol/l (1.5-2.28), P=0.79). By contrast, cortisol values were similar in patients and volunteers. CONCLUSIONS: In healthy volunteers, copeptin levels significantly increased after psychological stress testing; this response was blunted in patients with DI.