Biomedical subjects

M Haluzík

Publications and source records attributed to M Haluzík.

At least 19 recordsLinked to original sources

PubMed2000

[Relation between serum leptin levels, blood parameters and erythropoietin levels in hemodialyzed patients].

BACKGROUND: Serum leptin levels are significantly increased in hemodialysed patients compared to healthy subjects. There are some data suggesting the possible relationship of leptin and the regulation of haematopoiesis. The aim of our study was to compare serum leptin levels in two groups of hemodialysed patients: the group treated by recombinant human erythropoietin (n = 40) (HD + EPO), the group without erythropoietin treatment (HD) and the control group of healthy subjects (n = 20) to explore the influence of erythropoietin treatment on serum leptin levels. METHODS AND RESULTS: The tendency towards lower body fat content and higher serum leptin levels was found in both groups of HD patients compared to control group, but the differences did not reach statistical significance due to high variability of those parameters (leptinu levels: HD 19.5 +/- 18.5, HD + EPO 24.9 +/- 23.3, K 10.4 +/- 8.8 ng.ml-1). The erythrocyte count and haemoglobin levels in both groups of HD patients were significantly lower than in control group. The erythrocyte count and haemoglobin levels were significantly lower in HD patients treated by erythropoietin compared to untreated HD group. The leptin/body fat content ratio was significantly higher in HD patients compared to healthy subjects (HD 0.86 +/- 0.72, HD + EPO 0.92 +/- 0.78, K 0.35 +/- 0.21, p < 0.05). Serum leptin levels in all studied groups correlated positively with body fat content and negatively with erythrocyte count. No significant relationships of serum leptin levels to erythropoietin levels or other parameters studied were found in any of groups. CONCLUSIONS: Our study further supported the fact that serum leptin levels in HD patients are relatively higher than in healthy subjects. Serum leptin levels in HD patients treated by recombinant human erythropoietin did not significantly differ from HD patients without this treatment. Except of the negative correlation between serum leptin levels and the erythrocyte count no statistically significant relationships of serum leptin levels and the blood count parameters were found.

Blood Cell Count↗

PubMed2000

[Serum leptin levels and soluble leptin receptors in female patients with anorexia nervosa].

BACKGROUND: Leptin action in peripheral tissues is enabled by an interaction with specific transmembrane receptors. Several of leptin receptor isoforms were identified, including soluble leptin receptor isoform structurally identical to extracellular domain of the the long leptin receptor isoform. The soluble receptor isoform is released to the circulation and acts probably as leptin-binding factor. The aim of our study was to measure serum concentrations of the soluble leptin receptor in patients with anorexia nervosa and in the control group of healthy women. Relationships of soluble leptin receptor levels to body mass index (BMI), body fat content, serum leptin, TNF-alpha and insulin levels were also studied. METHOD AND RESULTS: 16 patients with anorexia nervosa and 16 age-matched lean healthy women were included into the study. All of the subjects were measured and weighed, the body fat content was estimated from the skinfold thickness measurement. The blood for the determination of leptin, soluble leptin receptor and other hormonal parameters was obtained from all subjects after the overnight fasting. BMI, body fat content, serum leptin and insulin levels in patients with anorexia nervosa were significantly lower than in the control group (BMI: 14.98 +/- 2.32 vs. 22.21 +/- 2.48, p < 0.01, % fat content: 16.43 +/- 4.56 vs. 27.19 +/- 4.59, p < 0.01, leptin: 1.37 +/- 1.85 ng.ml-1 vs. 7.19 +/- 3.49 ng.ml-1, p < 0.01, insulin: 12.97 +/- 2.89 mU.l-1 vs. 17.09 +/- 5.57 mU.l-1, p < 0.05). Serum soluble leptin receptor levels in patients with anorexia nervosa were significantly higher compared the to control group (24.67 +/- 8.3 U.ml-1 vs. 15.71 +/- 2.79 U.ml-1, p < 0.01). No significant differences in serum TNF-alpha levels between the groups studied were found. Serum leptin levels in both groups correlated positively with BMI and body fat content. Serum soluble leptin receptor levels in both groups correlated negatively with BMI only. No statistically significant relationships between serum soluble leptin receptor levels and the rest of parameters studied were found in any of the groups studied. CONCLUSIONS: Serum soluble leptin receptors levels in patients with anorexia nervosa were significantly higher in comparison with the healthy subjects. Except of the negative correlation between serum soluble leptin receptor levels and BMI no statistically significant relationships between serum soluble leptin receptor and the rest of parameters studied were found.

Anorexia Nervosa↗

PubMed2000

[Is leptin physiologically important in the regulation of hematopoiesis?].

Leptin is a protein hormone produced predominantly by adipocytes. Its serum concentrations under stabilised energy balance reflect the total body fat content. Serum leptin levels represent an important peripheral signal informing the hypothalamic satiety center about the body fat stores. Apart from the above mentioned functions the possible physiological significance of leptin in the regulation of angiogenesis, blood pressure, sexual maturation etc. is suggested. The long isoform of leptin receptor belongs to the cytokine receptors group. The leptin receptors were identified in some haematopoietic stem cells. Leptin was found to stimulate the proliferation of haematopoietic stem cells either alone or in combination with some cytokines. Leptin thus seams to represent an additional factor that plays a role in the haematopoiesis regulation as it was demonstrated by some experimental studies. However, this suggestion needs to be further confirmed by clinical studies exploring the changes of serum leptin levels in various phases of haematological diseases and during their treatment.

Animals↗

PubMed2000

Serum leptin levels in patients with hyperlipidemias.

Leptin is a protein hormone produced by adipocytes that reflects the body fat content. The aim of our study was to compare serum leptin levels in randomly selected untreated males and females with hypercholesterolemia and combined hyperlipidemia and in healthy control subjects matched for age and body mass index and to study the relations between leptin and serum lipids and lipoproteins. No statistically significant differences in serum leptin levels were found between the male control group (5.26 +/- 2.81 ng/mL(-1)) and the male group with hypercholesterolemia (8.16 +/- 3.85 ng/mL(-1)) or combined hyperlipidemia (7.51 +/- 4.83 ng/mL(-1)) and between the female control group (13.0 +/- 8.12 ng/mL(-1)) and the female group with hypercholesterolemia (15.36 +/- 8.89 ng/mL(-1)) or combined hyperlipidemia (18.63 +/- 10.15 ng/mL(-1)). Leptin concentration in male group with hypercholesterolemia did not differ significantly from the female control group; in the other male groups, leptin levels were significantly lower than those of the other female groups. Serum leptin levels in all studied groups except for the male group with hypercholesterolemia positively correlated with body mass index. Serum leptin levels correlated negatively with high-density lipoprotein cholesterol in the female group with hypercholesterolemia (r = -0.67, P < 0.01) and the male group with combined hyperlipidemia (r = -0.56, P < 0.01). A positive correlation between serum leptin and high-density lipoprotein cholesterol (r = 0.67, P < 0.01) and between leptin and lipoprotein (a) (r = 0.71, P < 005) was found in female group with combined hyperlipidemia. No other significant relationships between leptin and serum lipids or lipoproteins were found. We conclude that serum leptin levels in patients with hyperlipidemias do not significantly differ from those healthy control subjects matched by age and body mass index.

Adult↗

PubMed2000

Interaction between serum leptin levels and hypothalamo-hypophyseal-thyroid axis in patients with anorexia nervosa.

The main objective of the study was to evaluate the endocrinological picture of anorexia. Serum leptin levels are low in untreated anorexia nervosa (AN), but studies of the exact relationship between leptin, body weight and hormones of hypothalamo-hypophyseal-thyroid axis and the impact of refeeding in anorectics are limited. The sample consistent of 15 patients with anorexia nervosa before and 1 month after partial weight recovery, and 15 age-matched control subjects. The body mass index (BMI), leptin, plasma neuropeptide Y (NPY), serotonin, thyroxine (T4), triiodothyronine (T3) and reverse triiodothyronine (rT3) in serum were evaluated for each subject. The mean serum levels of leptin, T4, and T3 were significantly lower before weight recovery in 15 patients with AN than they were in control subjects. After partial weight recovery, basal T3 levels were unchanged and significantly lower than in controls. Basal T4 was even still more reduced, but we observed significantly elevated ratio of T3/T4 and reduced ratio rT3/T4 of in AN patients after gain recovery, indicating increased conversion of T4 to T3 than to rT3. The levels of serum leptin were low in AN, but after partial weight recovery slightly increased, and correlated with BMI. No differences were observed in serum NPY. Serum levels of IGF-1 and serotonin were lower in AN than in controls before and after partial weight gain. IGF-1 was slightly increased after partial weight gain. We did not find correlation between serum levels of leptin and serum T4. The low serum levels of T3 associated with chronic starvation were thought to be the result of impaired peripheral conversion of T4 to T3. However, decreased levels of T3 were still apparent even after a partial weight gain, and the concentration of T4 was even lower. The diminished serum level of TSH in AN, however, appeared to return to the level of controls. On the basis of these results, we assume that low serum levels of thyroid hormones in AN reflect a dysfunction of the HPT axis in AN patients. It is known that in man serum serotonin levels correlate positively with T3 levels. It is possible that the low serum levels of thyroid hormones in AN subjects result in low serum serotonin and its product, melatonin. While IGF-1 reflects the energy intake of the previous few weeks, the serum leptin concentration reflects the true status of the adipose stores, a fact that has useful clinical implications.

Anorexia Nervosa↗

PubMed2000

[Effect of physical activity on serum leptin levels].

Leptin is a protein hormone produced predominantly by adipocytes. Its serum concentrations usually reflect the total body fat content i.e. they are higher in obese than in lean subjects. The aim of our study was to follow the influence of the regular hard physical training on the serum leptin levels. Therefore, the serum leptin levels in top rugby players, top race walkers and age and gender-matched control group were compared. The relationship between serum leptin concentrations and body mass index and body fat content was also studied. It was found that serum leptin levels in rugby players were significantly higher than in race walkers group, but lower than in control one. Serum leptin levels in race walkers were lower than those of rugby players and of control group. The body fat content in race walkers was lower than in resting two groups. There was no significant difference in body fat content between control and rugby players group. Serum leptin levels correlated positively with body mass index and body fat content both in control and in rugby players group. No statistically significant relationship was found between leptin and body mass index or body fat content respectively in race walkers group. We conclude that serum leptin levels in top sportsmen are lower than in non-sporting healthy age and gender-matched controls. The lower leptin levels in top sportsmen are probably in part the result of lower body fat content and in part the result of complex neurohormonal adaptation on the long term physical training.

Adipose Tissue↗

PubMed2000

The regulation of adenohypophyseal prolactin secretion: effect of triiodothyronine and methylene blue on estrogenized rat adenohypophysis.

Estrogens and thyroid hormones contribute importantly to cell proliferation and tumor transformation in the pituitary gland. We found that methylene blue antagonized estrogen-promoted adenohypophyseal enlargement and the enhancement of prolactin secretion. The purpose of the present article is to provide a review about neurotransmitters and their receptors involved in estrogen-induced anterior pituitary growth and in the antagonistic effects of triiodothyronine (T3) and methylene blue (MB). Central dopaminergic and noradrenergic systems are the most important factors regulating pituitary growth and function. Recently nitric oxide (NO) was added to the list of the neurotransmitters and neuropeptides involved in the control of the anterior pituitary secretion. Our data suggest that estrogen-induced anterior pituitary growth is associated with decreased synthesis and metabolism of central catecholamines, reduction of adenohypophyseal beta-adrenergic receptors and increase of dopamine DA-2 receptors. We found that the treatment with T3 or MB prevented both estrogen-induced catecholaminergic inhibition and dopamine DA-2 receptor increment in the anterior pituitary. In contrast to T3, MB given alone also slightly decreased the anterior pituitary weight. Serum levels and anterior pituitary content of prolactin were increased after treatment with estradiol benzoate (EB), whereas T3 or MB partially attenuated prolactin hypersecretion after estrogen administration. This is in accord with the attenuation of EB-induced inhibition of dopaminergic system by T3 and MB. MB given in combination with EB also partially attenuated EB-promoted rise of adenohypohyseal NO synthase activity which plays an important role in the regulation of prolactin secretion. Further studies on central catecholaminergic systems, pituitary receptors, the nitrergic system and mechanisms of intracellular signal transduction are necessary for better understanding of pituitary tumor transformation and possibly for the discovery of new approaches towards treating patients with these diseases.

Adrenergic beta-Agonists↗

PubMed2000

The role of nitric oxide in the development of streptozotocin-induced diabetes mellitus: experimental and clinical implications.

The overproduction of the free radical nitric oxide (NO) by activated immunocompetent cells with subsequent development of local oxidative stress is supposed to be one of the possible pathophysiological mechanisms of beta-cell damage during streptozotocin-induced diabetes. The blockade of increased NO production by simultaneous administration of NO-synthase inhibitors partially suppresses the hyperglycemia and the increase of glycated hemoglobin concentration. Here we summarize the current state of knowledge concerning the modulation of streptozotocin-induced diabetes development by treatment with NO-synthase inhibitors including the partial inhibition of the changes in serum leptin levels. The differences in the reaction to streptozotocin administration between wild type mice and inducible NO-synthase knockout mice are also discussed. The overproduction of NO during the development of streptozotocin-induced diabetes is probably an important part of the complex autoimmune reaction which leads to the destruction of pancreatic beta-cells. Further clarification of the role of nitric oxide in streptozotocin-induced diabetes development could have important clinical implications.

Animals↗

PubMed1999

[The effect of partial refeeding on serum levels of leptin and resting energy expenditure in female patients with anorexia nervosa].

BACKGROUND: Serum leptin levels and resting energy expenditure are significantly decreased in patients with anorexia nervosa compared to healthy subjects. Partial realimentation of patients with anorexia nervosa increases both these parameters. However, there so far are no data concerning the relationship of serum leptin levels and resting energy expenditure in patients with anorexia nervosa. The aim of our study was to follow the relationship of serum leptin levels and resting energy expenditure in patients with anorexia nervosa before and after refeeding. METHODS AND RESULTS: It was found that serum leptin levels in patients with anorexia nervosa both before and after partial realimentation were significantly lower compared to healthy subjects (0.86 +/- 0.9 ng.ml-1 and 1.77 +/- 1.9 ng.ml-1 vs 6.85 +/- 3.0 ng.ml-1, p < 0.05). The total resting energy expenditure in patients with anorexia nervosa both before and after realimentation were significantly lower than in the control group (4973 +/- 979 and 5263 +/- 899 vs 6401 +/- 827 kJ/day, p < 0.05). When expressed per body weight the resting energy expenditure in patients with anorexia nervosa was significantly higher in comparison with the control group (122.3 +/- 20.6 and 121.5 +/- 14.2 vs 104.2 +/- 14.6 kJ/day, p < 0.05). The differences in resting energy expenditure in patients with anorexia nervosa before and after refeeding did not reach statistical significance. The body mass and the body fat content increased significantly after realimentation index (14.5 +/- 1.4 vs 15.6 +/- 1.5 kg.(m2)-1 and 14.9 +/- 3.4 vs 16.6 +/- 3.7, p < 0.05) but remained still below of those of control group (BMI 22.3 +/- 2.7, body fat content 26.9 +/- 4.2). CONCLUSIONS: Our study confirmed the reduced serum leptin levels and the total resting energy expenditure in patients with anorexia nervosa compared to healthy age-matched subjects. No statistically significant relationships were found between serum leptin levels and resting energy expenditure either in healthy subjects or in patients with anorexia nervosa before or after partial realimentation respectively.

Adolescent↗

PubMed1999

[Nutritional status of drug addicts in a methadone program].

BACKGROUND: Substitution treatment of drug addicts with methadone has been used in many countries for more than 35 years. In our country it was started in 1997. The objective was above all to evaluate the nutritional status and some biochemical parameters before and after 18 months of methadone substitution. METHODS AND RESULTS: A total of 14 patients were examined (9 men, 5 women), mean age 35 years, range 26-44 years, highly dependent on opiates: heroin, codeine and its derivatives). The examination was made before onset of treatment and after 18 months of treatment. The subjective feeling of all patients improved, they felt more active and efficient. The Kehlet score declined from 5.8 +/- 1.9 to 3.8 +/- 1.5. The body weight increased from 69.3 +/- 14.8 to 78.6 +/- 19.7 kg. BMI from 22.8 +/- 3.2 to 25.5 +/- 5.0 (kg/m2), the skinfold above the triceps muscle from 11.9 to 16.6 mm, prealbumin from 0.17 +/- 0.05 to 0.22 +/- 0.66 g/l). The handgrip strength did not increase, no significant changes were recorded in albumin and transferrin levels. The raised serum aminotransferase levels did not change (due to chronic hepatitis). CONCLUSIONS: Substitution treatment of drug addicts with methadone leads not only to improvement of the subjective state but also to objective signs of a better nutritional status.

Adult↗

PubMed1999

[Effect of aerobic training in top athletes on serum leptin: comparison with healthy non-athletes].

Leptin is a protein hormone produced by adipocytes. Its serum concentration in the most of cases precisely reflect the total body fat content. The aim of our study was to follow up the influence of regular aerobic training on serum leptin levels. Therefore the serum leptin levels, basic anthropometric parameters and serum lipids were compared in 11 intensively trained race walkers and 10 age-matched non sporting control subjects. We have found, that serum levels, body weight, body mass index, body fat content, total and LDL-cholesterol were significantly decreased in walkers group in comparison with control subjects. Serum leptin levels positively correlated with body fat content and body mass index only in control group, in the walkers group the correlation was non-significant. The results of our study demonstrate, that regular aerobic training accompanied with the decrease of body fat content leads to the significant drop of serum leptin levels.

Adipose Tissue↗

PubMed1999

Serum leptin levels in patients with anorexia nervosa before and after partial refeeding, relationships to serum lipids and biochemical nutritional parameters.

Leptin is a protein hormone produced by adipocytes that provide information about the body fat content. It was previously reported that serum leptin levels were decreased in patients with anorexia nervosa in comparison with healthy control subjects. The aim of our study was to compare serum leptin levels in patients with anorexia nervosa (n=11, initial mean BMI=15.4 kg/m2) before and after partial recovery with control age-matched subjects (n=11, mean BMI= 20.3 kg/m2) and to study the relationships of leptin levels, serum lipids and biochemical nutritional parameters. We found that serum leptin concentrations in patients with anorexia nervosa were significantly reduced in comparison with control subjects (3.61 vs 9.37 ng.ml(-1), p<0.01). Serum cholesterol, triglycerides, total protein and albumin in patients with anorexia nervosa either before or after partial recovery did not differ from the control group. After partial recovery, a significant increase in serum leptin was observed (4.83 vs 3.61 ng.ml(-1), p<0.05), but the values still remained significantly lower than in the control group (p<0.01) Leptin levels correlated positively with the body mass index in the control group and anorexia nervosa group before recovery. The correlation with BMI in the anorexia nervosa group after refeeding was not significant. No significant correlation was found between leptin concentrations and serum lipids, total protein, albumin and prealbumin, respectively. Serum leptin thus represents a sensitive parameter that reflects the nutritional status in patients with anorexia nervosa suitable for long-term follow up during refeeding therapy.

Adult↗

PubMed1999

Serum leptin concentrations in patients with combined hyperlipidemia: relationship to serum lipids and lipoproteins.

Leptin is a protein hormone produced predominantly by adipocytes. Serum leptin concentrations in healthy individuals positively correlate with the body fat content and body mass index, i.e. they are higher in obese than in lean subjects. The relations between serum leptin concentration and serum lipids and lipoproteins is not yet clear. The aim of our study was to compare serum leptin concentrations in 22 randomly selected patients with untreated combined hyperlipidemia and 19 healthy control subjects matched for age and the body mass index. The relationship was studied between serum leptin concentrations and serum lipids (total, HDL, LDL cholesterol and triglycerides) and lipoproteins (lipoprotein (a), apolipoprotein B). It was found that serum leptin levels in patients with combined hyperlipidemia did not significantly differ from those of control subjects (6.69+/-4.3 vs 5.78+/-3.2 ng.ml(-1)). Serum leptin concentrations in both groups correlated positively with the body mass index. The relationship between leptin concentrations and lipid or lipoprotein levels found in any of the studied groups was not statistically significant. We conclude that serum leptin concentrations in patients with combined hyperlipidemia as well as in healthy control subjects reflect the body fat content and have no significant relation to serum lipids or lipoproteins.

Adult↗

PubMed1999

[Relation of serum leptin levels and regulation of resting energy expenditure].

Leptin is a protein hormone produced by adipocytes. Its serum concentrations in the most of cases positively correlate with total body fat content and body mass index (BMI). Leptin plays a role in the food intake regulation. It also increases resting energy expenditure in hypoleptinaemic ob/ob mice. Its relationship to resting energy expenditure in human is less clear. The aim of our study was to follow the serum leptin levels in healthy females (n = 12) and males (n = 14) and their relationship to resting energy expenditure, body fat content, other antropometric and nutritional biochemical parameters. It was found that serum leptin levels were significantly higher in females comparing to males (6.8 +/- 3 ng.ml-1 vs. 2.6 +/- 1 ng.ml-1, p < 0.05). The serum leptin levels correlated positively with body fat content and body mass index in both groups. In females the positive correlation between body weight and serum leptin levels was found. No statistically significant relationship between serum leptin levels and resting energy expenditure, serum total protein, albumin or prealbumin concentration was found in any of studied groups. The results of our study do not testify to direct relationship between serum leptin levels and resting energy expenditure in young healthy individuals.

Adult↗

PubMed1999

[Serum leptin levels in female patients with protein-calorie malnutrition and its relation to biochemical indicators of nutritional status].

Leptin is a protein hormone produced by adipocytes. Its serum concentrations in the most of cases positively correlate with total body fat content. Serum leptin levels are increased in obese in comparison with lean subjects. Leptin levels in females are two or three times higher than in body mass index and age-matched males. The aim of our study was to investigate the serum leptin concentrations in females with protein-caloric malnutrition of various aetiology, the relationship between leptin levels and biochemical nutritional parameters and to compare the values with those of age-matched control group. Totally 12 patients with malnutrition of various aetiology and 14 control age-matched healthy subjects were included into the study. It was found that serum leptin levels were significantly decreased in malnutrition group in comparison with control group (3.09 +/- 1.33 ng.ml-1 vs 9.42 +/- 2.76 ng.,l-1, p < 0.05). A significant decrease in body mass index, serum total protein, albumin, prealbumin, cholesterol and triglycerides concentration was also found in malnutrition in comparison with control group. While a strong positive correlation between leptin concentrations and body mass index was found in control group (r = 0.72, p < 0.05), no statistically significant relation between leptin and body mass index was observed in malnutrition group. Furthermore, no significant relationship was found between serum leptin levels and serum total protein, albumin, prealbumin, cholesterol and triglycerides neither in control or in malnutrition group. We conclude that serum leptin levels in patients with malnutrition are significantly decreased in comparison with age-matched healthy control subjects. The loss of positive correlation between leptin and body mass index in malnutrition group is explainable by the changes of body composition in patient with malnutrition. The body mass index value in these patients reflects the total body fat content less precisely than in healthy controls.

Biomarkers↗

PubMed1998

[Nitric oxide--its effects and significance in the human body].

Nitric oxide is a reactive gas with series of important functions in human body. An important deal of nitric oxide in the etiology and pathogenesis of series of autoimmune diseases, degenerative diseases of central nervous system etc. is suggested. This article summarizes the current knowledge about NO mean in medicine with impact to a perspective possibility of influence of any diseases by modulation of nitric oxide synthesis.

Humans↗

PubMed1998

The changes of the thyroid function and serum testosterone levels after long-term L-NAME treatment in male rats.

Nitric oxide is a highly reactive gas that is produced by many tissues and exerts a series of physiological and pathophysiological effects. We studied the changes of the serum testosterone, thyroxine and thyrotropin levels, thyroid and anterior pituitary weights and thyroid cGMP concentrations in male Wistar strain rats treated with estradiol benzoate (EB) (1 mg/kg, im twice a week) and nonselective NO-synthase inhibitor L-NAME (N-omega-nitro-L-arginine methyl ester) alone and with combination of these substances. We have found that L-NAME in a dose 100 mg/kg/day but not in a dose 50 mg/kg/day increased the serum thyroxine and testosterone levels and in the case of testosterone in a higher dose partially blocked its drop when administered simultaneously with EB. The serum thyrotropin levels significantly fell after L-NAME and EB treatment. The cGMP thyroid levels changed only slightly in groups treated EB and L-NAME alone and were significantly decreased in group treated with combination of these substances. The nitric oxide thus seems to be an important modulator of thyroid and testicular function. The cGMP activation cascade is not probably involved in the nitric oxide induced changes of thyroid function.

Animals↗

PubMed1998

Lower serum leptin concentrations in rugby players in comparison with healthy non-sporting subjects--relationships to anthropometric and biochemical parameters.

Leptin is a protein hormone synthesized by adipocytes. Its serum concentrations reflect the total body fat content. Serum leptin concentrations are significantly higher in obese than in lean people and in women than in men. However little information about the influence of physical activity on serum leptin concentrations is available. We have compared the body weight, the body mass index (BMI), the body fat content (measured by caliper as skinfold thickness) and the serum concentrations of leptin, triglycerides, total, high density and low density lipoprotein (LDL) cholesterol in 14 top rugby players and 10 healthy controls. We found that serum leptin, total and LDL cholesterol concentrations were significantly lower in the rugby players group than in the control subjects. The body weight and BMI were significantly higher in the rugby players, while the body fat content was only slightly (non-significantly) higher in the control group. The serum leptin concentrations in both groups positively correlated with the BMI and body fat content and also with LDL concentrations in the control group. The serum leptin concentrations in the rugby players were lower than in the non-sporting subjects despite a similar body fat content in both groups. We would therefore suggest the possibility that regular hard physical training decreases serum leptin concentrations not only by the decrease of total body fat content, but also by a separate mechanism, which is not directly dependent on the changes in the amount of body adipose tissue.

Adipose Tissue↗