Changes of plasma obestatin, ghrelin and NPY in anorexia and bulimia nervosa patients before and after a high-carbohydrate breakfast.

Peptides ghrelin, obestatin and neuropeptide Y (NPY) play an important role in regulation of energy homeostasis, the imbalance of which is associated with eating disorders anorexia (AN) and bulimia nervosa (BN). The changes in ghrelin, obestatin and NPY plasma levels were investigated in AN and BN patients after administration of a high-carbohydrate breakfast (1604 kJ). Eight AN women (aged 25.4+/-1.9, BMI: 15.8+/-0.5), thirteen BN women (aged 22.0+/-1.05, BMI: 20.1+/-0.41) and eleven healthy women (aged 25.1+/-1.16, BMI: 20.9+/-0.40) were recruited for the study. We demonstrated increased fasting ghrelin in AN, but not in BN patients, while fasting obestatin and NPY were increased in both AN and BN patients compared to the controls. Administration of high-carbohydrate breakfast induced a similar relative decrease in ghrelin and obestatin plasma levels in all groups, while NPY remained increased in postprandial period in both patient groups. Ghrelin/obestatin ratio was lower in AN and BN compared to the controls. In conclusions, increased plasma levels of fasting NPY and its unchanged levels after breakfast indicate that NPY is an important marker of eating disorders AN and BN. Different fasting ghrelin and obestatin levels in AN and BN could demonstrate their diverse functions in appetite and eating suppression.

[Neuropeptide Y, ghrelin and leptin plasma levels in anorexia nervosa patients and their changes during six-week refeeding]. / Plazmatické hladiny neuropeptidu Y, ghrelinu a leptinu a pacientek s anorexia nervosa a jejich zmeny po sestitýdenní realimentaci.

OBJECTIVE: Anorexia nervosa (AN) is characterized by markedly changes in hormone secretion influencing food intake, energy homeostasis and long-term body weight regulation. The aim of this study was to determine neuropeptide Y (NPY), ghrelin and leptin plasma levels and their changes after six weeks of nutritional-rehabilitation program in severely malnourished anorexia nervosa patients. METHODS: Ten women with DSM-IV diagnosed anorexia nervosa, hospitalized (BMI 14.74 +/- 0.43; age 23.3 +/- 1.0) and ten age-matched healthy women (BMI 21.45 +/- 0.72; age 24.3 +/- 0.8) were enrolled to the study. Fasting plasma levels of NPY, ghrelin and leptin were measured before and after the treatment. RESULTS: Fasting plasma ghrelin and NPY levels were significantly increased in AN patients comparing to healthy women, while plasma leptin was decreased. After six weeks of the treatment plasma ghrelin levels significantly decreased and plasma leptin levels increased. Plasma NPY levels didn't change during the treatment, average BMI significantly increased in AN patients. CONCLUSIONS: We confirmed that ghrelin and leptin plasma levels express actual nutritional status of a body and did change during the six-weeks refeeding in AN patients. Plasma leptin levels together with constantly increased NPY levels indicate to persisting dysregulation of appetite and body weight control mechanisms in AN patients.

Serum visfatin levels in patients with anorexia nervosa and bulimia nervosa.

Visfatin is an adipose tissue-derived hormone shown to correlate with visceral fat mass in patients with obesity. Its possible role in patients with different types of eating disorders is unknown. We measured fasting serum levels of visfatin and leptin and surrogate measures of insulin sensitivity in 10 untreated patients with anorexia nervosa (AN), 10 untreated patients with bulimia nervosa (BN) and 20 age-matched healthy women (C) to study the possible role of visfatin in these disorders. Patients with AN had severely decreased body mass index (BMI) and body fat content. BMI of BN group did not significantly differ from that of C group, whereas body fat content of BN group was significantly lower compared to C and higher compared to AN group, respectively. Serum glucose levels did not significantly differ among the groups studied, whereas serum insulin and leptin levels and HOMA index were significantly decreased in AN group relative to both C and BN group. In contrast, serum visfatin levels in both patients with AN and BN did not differ from those of C group. We conclude that circulating visfatin levels are not affected by the presence of chronic malnutrition in AN or binge/purge eating behavior in BN.

Plasma obestatin levels in normal weight, obese and anorectic women.

Obestatin is a recently discovered peptide produced in the stomach, which was originally described to suppress food intake and decrease body weight in experimental animals. We investigated fasting plasma obestatin levels in normal weight, obese and anorectic women and associations of plasma obestatin levels with anthropometric and hormonal parameters. Hormonal (obestatin, ghrelin, leptin, insulin) and anthropometric parameters and body composition were examined in 15 normal weight, 21 obese and 15 anorectic women. Fasting obestatin levels were significantly lower in obese than in normal weight and anorectic women, whereas ghrelin to obestatin ratio was increased in anorectic women. Compared to leptin, only minor differences in plasma obestatin levels were observed in women who greatly differed in the amount of fat stores. However, a negative correlation of fasting obestatin level with body fat indexes might suggest a certain role of obestatin in the regulation of energy homeostasis. A significant relationship between plasma obestatin and ghrelin levels, independent of anthropometric parameters, supports simultaneous secretion of both hormones from the common precursor. Lower plasma obestatin levels in obese women compared to normal weight and anorectic women as well as increased ghrelin to obestatin ratio in anorectic women might play a role in body weight regulation in these pathologies.

Simultaneous decrease of plasma obestatin and ghrelin levels after a high-carbohydrate breakfast in healthy women.

Ghrelin is a gut peptide produced mainly by stomach, well known to induce appetite stimulatory actions. Obestatin, a recently identified peptide derived from preproghrelin, was initially described to antagonize stimulatory effect of ghrelin on food intake. The postprandial response of obestatin and its relationship with ghrelin in humans remains unknown. We therefore investigated the postprandial response of obestatin and total ghrelin, acyl and desacyl ghrelin and neuropeptide Y (NPY) to a high-carbohydrate breakfast (1 604 kJ) in eight healthy women (age: 24.2+/-0.82 years; BMI 21.6+/-0.61 kg/m(2)). Blood samples were collected before the meal, and 30, 60, 90, 120 and 150 min after the breakfast consumption. Postprandial plasma obestatin concentrations significantly decreased compared with preprandial levels as well as total ghrelin concentrations and reached the lowest values 90 and 120 min after the meal consumption, respectively (p<0.05). Plasma acyl and desacyl ghrelin concentrations decreased after the breakfast and reached lowest values in 30 and 60 min, respectively (p<0.05). Plasma NPY concentrations were lower than preprandial levels 90 and 150 min after consuming breakfast (p<0.05). In conclusion, we demonstrated in healthy young women that plasma obestatin concentrations decrease similarly to ghrelin after a high-carbohydrate breakfast.

Hormonal and psychobehavioral predictors of weight loss in response to a short-term weight reduction program in obese women.

Among the factors influencing weight loss and maintenance, psychobehavioral, nutritional, metabolic, hormonal and hereditary predictors play an important role. Psychobehavioral factors influence adherence to lifestyle changes and thus weight loss maintenance. The outcome of short-term weight reduction treatment is mainly affected by changes in energy and nutrient intake and physical activity and thus the impact of hormones can possibly be obscured. In order to reveal hormonal determinants of weight loss, a 4-week in-patient comprehensive weight reduction program was introduced in which food intake and physical activity were under the strict control. Women (n = 67, BMI: 32.4+/-4.4 kg; age: 48.7+/-12.2 years) who exhibited stable weight on a 7 MJ/day diet during the first week of weight management were given a hypocaloric diet yielding daily energy deficit 2.5 MJ over the subsequent 3-week period. This treatment resulted in a mean weight loss of 3.80+/-1.64 kg. Correlation analysis revealed that baseline concentrations of several hormones were significantly associated either with a higher (free triiodothyronine, C-peptide, growth hormone, pancreatic polypeptide) or with a lower (insulin-like growth factor-I, cortisol, adiponectin, neuropeptide Y) reduction of anthropometric parameters in response to weight management. In a backward stepwise regression model age, initial BMI together with baseline levels of growth hormone, peptide YY, neuropetide Y and C-reactive protein predicted 49.8 % of the variability in weight loss. Psychobehavioral factors (items of the Eating Inventory, Beck Depression score) did not contribute to weight change induced by a well-controlled short-term weight reduction program.

Impact of cardiopulmonary bypass on peripheral tissue metabolism and microvascular blood flow.

The aim of this study was to monitor and compare the changes in metabolism and blood flow in the skeletal muscles during cardiac operations performed with cardiopulmonary bypass (CPB) and operations without CPB (off-pump) by means of interstitial microdialysis (Figure 1). Surgical revascularization, coronary artery bypass grafting (CABG), was performed in 40 patients randomized to two groups. Twenty patients (On-Pump Group) were operated on using CPB, 20 patients (Off-Pump Group) were operated on without CPB. Interstitial microdialysis was performed by 2 probes of a CMA 60 (CMA Microdialysis AB, Solna, Sweden) inserted into the patient's deltoid muscle. Microdialysis measurements were performed at 30-minute intervals. Glucose, lactate, pyruvate and glycerol as markers of basic metabolism and tissue perfusion were measured in samples from the first probe, using a CMA 600 Analyzer (CMA Microdialysis AB). Blood flow through the interstitium was monitored by means of dynamic microdialysis of ethanol as a flow-marker in the dialysates taken from the second probe (ethanol dilution technique). Results in both the groups were statistically processed and compared. Both the groups were similar in respect of preoperative characteristics. Dynamic changes of interstitial concentrations of the measured analytes were found in both the patient groups (on-pump vs. off-pump) during the operation. There was no significant difference in dialysate concentrations of glucose and lactate between the groups. Significant differences were detected in pyruvate and glycerol interstitial concentrations, lactate/pyruvate ratio and lactate/glucose ratio between the on-pump vs. off-pump patients. In the Off-Pump Group, pyruvate concentrations were higher and the values of concentrations of glycerol lower. The lactate/pyruvate ratio and the lactate/glucose ratio, indicating the aerobic and anaerobic tissue metabolism status, were lower in the Off-Pump Group. There was no significant difference in dialysate concentrations of ethanol as a flow-marker during the surgery in either of the groups. There was no statistically significant difference between the groups (On-Pump Group vs. Off-Pump Group) comparing the postoperative clinical outcome (ICU stay, ventilation duration, length of hospital stay). The dynamic changes in the interstitial concentrations of the glucose, glycerol, pyruvate and lactate were found in both the groups of patients (On-Pump Group and Off-Pump Group), but there was no difference in local blood flow when the ethanol dilution technique was used. These results showed significantly higher aerobic metabolic activity of the peripheral tissue of patients in the Off-Pump Group vs. the On-Pump Group during the course of cardiac revascularization surgery. Results suggest that extracorporeal circulation, cardiopulmonary bypass, compromises peripheral tissue (skeletal muscles) energy metabolism. These changes have no impact on the postoperative clinical outcome; no significant difference between the groups was found.

Calcium intake and the outcome of short-term weight management.

Experimental and epidemiological studies suggest that calcium intake is inversely related to weight gain. Calcium of dairy origin has been shown to be more effective in promoting weight loss. However, clinical studies yielded controversial results concerning the role of calcium intake in weight change. The aim of this study was to ascertain whether the addition of calcium can affect the outcome of 3-week weight management (WM) with a hypocaloric diet characterized by a decreased calcium intake. Overweight/ obese women (n=67; BMI 32.2+/-4.1 kg/m(2); age 49.1+/-12.1 years) underwent a 4-week comprehensive WM program. WM included a 7 MJ/day diet resulting in a stable weight during the first week and a 4.5 MJ/day diet with mean daily calcium intake 350 mg during the second to fourth week. Participants were divided into three age- and BMI-matched groups who received placebo or calcium (500 mg/day). Calcium was administered either as carbonate or calcium of dairy origin (Lactoval). There was no significant difference in weight loss in response to WM between the placebo-treated and calcium-treated groups. However, addition of calcium to the diet resulted in a lower hunger score in the Eating Inventory as well as a decrease in plasma resistin levels. Body composition measured by bioimpedance demonstrated that added calcium leads to preservation of fat-free mass. Nevertheless, a greater loss of fat-free mass in the placebo group might be partly due to a greater loss of water.

[Influence of early postnatal nutrition in preterm infants on their anthropometric and hormonal characteristics at the age of 10 years]. / Vliv casné postnatální výzivy u predcasne narozených detí na jejich antropometrické a hormonální charakteristiky ve veku 10 let.

BACKGROUND: [corrected] A protective effect of breast feeding on the development of obesity has been clearly demonstrated. Several studies associated higher protein intake in postnatal period with the earlier "adiposity rebound" and the higher BMI in later life. METHODS AND RESULTS: Twenty eight girls born at 34th week of pregnancy (weight: 2.22+/-0.31 kg, length: 45.2+/-2.5 cm, BMI: 11.0+/-1.5 kg/m(2)), were subdivided in two groups differing in protein intake during the first postnatal month due to either breast feeding or formula feeding (113.5+/-18.7 g/month vs. 174.00+/-14.3 g/month; p<0.0001). Groups did not differ in average body weight, height and BMI at birth. Anthropometric and hormonal characteristics, body composition, energy and macronutrient intakes were determined at the age of 10 years in girls together with parental BMI. Association between the early postnatal nutrition and anthropometric and hormonal indexes at 10 years was evaluated. No significant differences between the groups in anthropometric and hormonal characteristics were found at 10 years except for IGF-1 which was significantly higher in the group with increased postnatal protein intake. Protein intake during the first postnatal month was not related to fat mass and leptin levels at 10 years. Protein intake during the first postnatal month significantly correlated with IGF-l level, BMI and body circumferences at 10 years. Postnatal fat intake correlates with body circumferences and IGF-1 and also with sagital diameter and leptin at 10 years. CONCLUSIONS: Early postnatal nutrition could encode IGF-1 in later life and this way may be involved in body size programming. Factor analysis revealed IGF-1 as a link between the postnatal energy and macronutrient intake and anthropometric indices and leptin at the age of 10 years.

Dynamic changes of orexin A and leptin in obese children during body weight reduction.

In this study, we describe changes of plasma levels of the hypothalamic neuropeptide orexin A in obese children during the reduction of body weight and its relationship to other biochemical and anthropometrical parameters. We measured orexin A fasting plasma levels by the RIA method in 58 obese children--33 girls and 25 boys; mean age 13.1+/-0.38 years (range 7-18.5) before and after 5 weeks of weight-reduction therapy. Leptin, IGF-1, and IGFBP-3 levels were measured in all the subjects and were compared to orexin A levels and anthropometrical data. Average weight in subjects before weight-reduction was 74.2+/-2.79 kg and after weight-loss 67.4+/-2.60 kg (p<0.0001). Orexin A levels before the therapy were 33.3+/-1.97 pg/ml and after the therapy 51.7+/-3.07 pg/ml (p<0.0001). Levels of orexin A were not significantly different between girls and boys (p=0.7842). We found negative correlation between orexin A and age (r = -0.5395; p<0.0001), body height (r = -0.4751; p=0.0002), body weight (r = -0.4030; p=0.0017) and BMI (r = -0.2607; p=0.0481). No correlation was found between orexin A and IGF-1, IGFBP-3 or leptin. Orexin A plasma levels increased during body weight loss, whereas the reverse was true for leptin levels. These findings support the hypothesis that orexin A may be involved in regulation of nutritional status in children.

Increased insulin sensitivity in patients with anorexia nervosa: the role of adipocytokines.

Anorexia nervosa (AN) is characterized by self-induced starvation leading to severe weight and fat loss. In the present study, we measured fasting plasma levels of adiponectin, leptin, resistin, insulin and glucose in 10 women with a restrictive type of AN and in 12 healthy women (C). Insulin sensitivity was determined according to homeostasis model assessment of insulin resistance (HOMA-R). Plasma resistin, leptin and insulin levels were significantly decreased, whereas plasma adiponectin levels were significantly increased in patients with AN compared to the C. HOMA-R was significantly decreased in patients with AN compared to the C group. Plasma adiponectin and leptin concentrations negatively and positively correlated with the body mass index and percentage body fat in both groups. Plasma adiponectin levels were negatively related to plasma insulin levels in the AN group only. In conclusion, we demonstrated that AN is associated with significantly decreased plasma leptin and resistin levels, markedly increased plasma adiponectin levels and increased insulin sensitivity. Plasma leptin and adiponectin levels were related to the body size and adiposity. Hyperadiponectinemia could play a role in increased insulin sensitivity of patients with AN. Neither body size and adiposity nor insulin sensitivity are the major determinants of plasma resistin levels in AN.

[The role of adiponectin in increased insulin sensitivity of patients with anorexia nervosa]. / Uloha adiponektinu pri zvýsené inzulinové senzitivite u pacientek s anorexia nervosa.

The aim of the present study was to determine the relationship between plasma levels of adipocytokine adiponectin and the degree of insulin sensitivity in patients with anorexia nervosa (AN). AN is a psychiatric disorder characterized mainly by severe malnutrition and loss of body fat. We measured fasting plasma adiponectin, insulin and glucose levels in ten women with a restrictive type of AN and in twelve healthy normal-weight women. Plasma adiponectin levels were significantly increased in patients with AN compared to healthy women (p < 0.01) and were negatively related to body mass index and percent body fat in both groups. Plasma adiponectin levels were negatively related to plasma insulin levels in the AN group only. Using homeostasis model assessment of insulin resistance (HOMA-IR), we found significantly increased insulin sensitivity in patients with AN compared to control women (p < 0.05). In conclusion, hyperadiponectinemia in patients with AN might contribute to increased insulin sensitivity in these patients.

Increased lipolysis of subcutaneous abdominal adipose tissue and altered noradrenergic activity in patients with Cushing's syndrome: an in-vivo microdialysis study.

Cushing's syndrome is associated with typical central redistribution of adipose tissue. The aim of the study was to assess lipolysis and catecholamines and their metabolites in subcutaneous abdominal adipose tissue using an in-vivo microdialysis technique. Nine patients with Cushing's syndrome and nine age-, gender- and body mass index (BMI)-matched control subjects were included in the study. Local glycerol concentrations were significantly increased in subcutaneous adipose tissue of patients with Cushing's syndrome (p<0.001). Plasma noradrenaline, dihydroxyphenylglycol and dihydroxyphenylalanine were decreased in patients with Cushing's syndrome (p<0.02, p<0.05, and p<0.02, respectively). Adrenaline, noradrenaline, dihydroxyphenylglycol and dihydroxyphenylalanine concentrations in subcutaneous abdominal adipose were non-significantly higher in patients with Cushing's syndrome. In conclusion, we showed that lipolysis in subcutaneous adipose tissue of patients with Cushing's syndrome is significantly increased as compared to healthy subjects. This finding together with non-significantly increased local catecholamine concentrations in these patients suggests a possible link between increased lipolysis and catecholaminergic activity in subcutaneous adipose tissue.

Adiponectin, an adipocyte-derived protein.

Adipose tissue is a hormonally active tissue, producing adipocytokines which may influence activity of other tissues. Adiponectin, abundantly present in the plasma increases insulin sensitivity by stimulating fatty acid oxidation, decreases plasma triglycerides and improves glucose metabolism. Adiponectin levels are inversely related to the degree of adiposity. Anorexia nervosa and type 1 diabetes are associated with increased plasma adiponectin levels and higher insulin sensitivity. Decreased plasma adiponectin levels were reported in insulin-resistant states, such as obesity and type 2 diabetes and in patients with coronary artery disease. Activity of adiponectin is associated with leptin, resistin and with steroid and thyroid hormones, glucocorticoids, NO and others. Adiponectin suppresses expression of extracellular matrix adhesive proteins in endothelial cells and atherosclerosis potentiating cytokines. Anti-atherogenic and anti-inflammatory properties of adiponectin and the ability to stimulate insulin sensitivity have made adiponectin an important object for physiological and pathophysiological studies with the aim of potential therapeutic applications.

Increased subcutaneous abdominal tissue norepinephrine levels in patients with anorexia nervosa: an in vivo microdialysis study.

The present study was designed to measure interstitial levels of norepinephrine-regulating lipolysis (NE) in subcutaneous abdominal adipose tissue of anorexia nervosa (AN) patients and control subjects under basal conditions and after the local administration of an inhibitor of NE re-uptake, maprotiline. In vivo microdialysis technique was used to assess subcutaneous adipose NE levels in five women with AN (body mass index 14.62+/-0.47 kg/m(2)) and six age-matched controls (22.1+/-0.52 kg/m(2)). NE was assayed using high performance liquid chromatography with electrochemical detection after batch alumina extraction. Measured basal adipose tissue NE levels reflecting its interstitial levels were significantly increased in AN patients compared to the controls (106.0+/-20.9 vs. 40.0+/-5.0 pg/ml). The local maprotiline administration resulted in a significant increase in adipose tissue NE levels (AN patients: 440.0+/-28.6 vs. 202.0+/-33.0 pg/ml in the controls) in both groups. Markedly increased subcutaneous abdominal adipose tissue NE levels in AN patients compared to control subjects reflect increased sympathetic nervous system activity but not altered membrane noradrenergic transporter system in anorexia nervosa patients.

Basal and exercise-induced sympathetic nervous activity and lipolysis in adipose tissue of patients with anorexia nervosa.

BACKGROUND: The sympathetic nervous system plays an important role in the regulation of adipose tissue (AT) lipolysis, which is a key step in the metabolic processes leading to the decrease of fat mass. The present study was designed to determine in vivo basal and exercise-stimulated lipolysis and concentrations of catecholamines, the major hormones controlling lipolysis, in subcutaneous abdominal AT in patients with anorexia nervosa (AN), characterized by self-induced starvation and excessive exercises resulting in severe malnutrition and fat store loss. The results of local catecholamines and glycerol levels were compared with those in plasma in both experimental groups. MATERIAL AND METHODS: An in vivo microdialysis technique was used for the assessment of norepinephrine, dihydroxyphenylalanine, dihydroxyphenylacetic acid and glycerol concentrations in subcutaneous AT of 10 women with AN (body mass index: 15.57 +/- 0.55 kg m(-2)) and 10 age-matched controls (body mass index: 21.56 +/- 0.41 kg m(-2)). Both the AN patients and the control subjects underwent a 1.5 W kg(-1) exercise test. RESULTS: Basal AT norepinephrine concentrations were increased in the AN patients in comparison with the controls. Basal AT glycerol concentrations were similar in both groups. During exercise, a local increase in the AT norepinephrine and glycerol concentrations was observed in the AN patients only. In contrast to the controls, the basal AT dihydroxyphenylalanine and dihydroxyphenylacetic acid levels in the AN patients were high and remained unchanged during exercise. Basal and exercise-stimulated plasma norepinephrine, dihydroxyphenylalanine, dihydroxyphenylacetic acid and glycerol levels were not different in the AN patients and healthy controls. CONCLUSION: Our study provides evidence of elevated baseline and exercise-induced sympathetic nervous activity and exercise-induced lipolysis in abdominal AT of AN patients.

Application of in vivo microdialysis to measure leptin concentrations in adipose tissue.

Microdialysis is a relatively new in vivo sampling technique, which allows repeated collecting of interstitial fluid and infusion of effector molecules into the tissue without influencing whole body function. The possibility of using microdialysis catheter with a large-pore size dialysis membrane (100 kDa) to measure concentrations of the adipocyte-derived peptide hormone leptin in interstitial fluid of adipose tissue was explored. Krebs-Henseleit buffer with 40 g/l dextran-70 was used to prevent perfusion fluid loss across the dialysis membrane. The relative recovery of leptin in vitro was determined using CMA/65 microdialysis catheter (100 kDa cut-off, membrane length 30 mm; CMA, Stockholm, Sweden) and four perfusion rates were tested (0.5, 1.0, 2.0, 5.0 microl/min). Furthermore, the microdialysis catheter CMA/65 was inserted into subcutaneous abdominal adipose tissue of 11 healthy human subjects and leptin concentrations in the interstitial fluid of adipose tissue in vivo were measured. The present findings are the first documentation on the use of microdialysis to study local leptin concentrations in the interstitial fluid of adipose tissue.

[Use of the in vivo microdialysis technique in basic and clinical research]. / Vyuzití mikrodialyzacní techniky in vivo v základním a klinickém výzkumu.

Microdialysis is in vivo technique that permits monitoring of local concentrations of metabolites and drugs at specific sites in the body that makes it an attractive tool for the basic and clinical research. Microdialysis entered the experimental studies of the brain, and later also of the peripheral tissues such as adipose and muscle tissues, kidney, lung, eye, skin, and blood. There are several critical factors in the experimental implementations of microdialysis: the probe, the perfusion solution, tissue integrity, and the sensitivity of microdialysate analysis method. When the experimental conditions are optimised to give valid results, microdialysis can provide numerous data from the relatively small number of individual subjects. It can bring about detailed clinical information reflecting free metabolite and drug concentrations in studied tissues and/or in plasma. With the progress of analytical methods, applications and importance of the microdialysis technique in clinical and pharmacokinetic research and diagnostics will increase.

[Recently discovered hormones with a role in energy homeostasis]. / Nedávno objevené hormony s úcastí v energetické homeostázi.

Adipocytal hormones resistin and adiponectin and gastric peptide ghrelin are recently discovered hormones, which are considered to take part in energy metabolism regulation. Resistin is expressed in adipose tissue only and its increased levels could cause insulin resistance and thus link obesity with type 2 diabetes. Adiponectin, as well as resistin, are products of genes, expressed in adipose tissue. Adiponectin could prevent development of aterosclerosis and it could play a role in anti-inflammatory reactions. Ghrelin is produced mainly in the stomach. Beside its role in long-term regulation of energy metabolism, it is involved in the short-term regulation of feeding. Main roles of resistin, adiponectin and ghrelin are summarised in the presented overview.

[Relation between serum leptin levels and selected nutritional parameters in hemodialyzed patients]. / Vztah sérových koncentrací leptinu a vybraných nutricních parametru u hemodialyzovaných pacientu.

Leptin is a protein hormone produced predominantly by adipocytes. Its serum concentrations positively correlate with body fat content and body mass index (BMI) i.e. they are lower in lean than obese subjects. The aim of our study was to compare serum levels of leptin, selected nutritional parameters and serum lipids in hemodialysed patients (n = 46) and healthy subjects (n = 24) and to explore the relationship between serum leptin levels and the rest of nutritional parameters in both groups. The tendency towards higher serum leptin levels in hemodialysed patients compared to control group was found, but the difference did not reach the statistical significance (24.31 +/- 24.06 ng/ml vs. 7.97 +/- 4.4 ng/ml). The leptin/body fat content ratio was significantly higher in hemodialysed patients compared to control subjects (0.85 +/- 0.74 vs. 0.27 +/- 0.11, p plain 0.01). The serum total protein, transpherine, albumin and cholesterol levels were significantly lower in hemodialysed patients compared to control group (68.14 +/- 5.56 g/l vs. 75.53 +/- 3.43 g/l; 2.04 +/- 0.49 g/l vs. 2.5 +/- 0.23 g/l; 33.65 +/- 2.86 g/l vs. 48.38 +/- 3.5 g/l; 4.56 +/- 1.19 mmol/l vs. 5.82 +/- 0.98 mmol/l; p = 0.001). Serum triglyceride levels were significantly lower in hemodialysed patients compared to controls (1.29 +/- 0.5 mmol/l vs. 2.31 +/- 1.23 mmol/l, p < 0.0001). Serum leptin levels in hemodialysed patients correlated positively with body fat content, serum cholesterol and triglyceride levels. In the control group only the significant positive correlation with body fat content was found. In conclusion, this study demonstrated relatively higher serum leptin levels in hemodialysed patients compared to healthy subjects, although their nutritional status expressed by serum protein nutritional parameters and body fat content is significantly impaired. Except of the positive correlation with serum lipids levels no statistically significant relationships between serum leptin levels and biochemical nutritional parameters were found in our study.