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12. Pinealectomy Increases and Exogenous Melatonin Decreases Leptin Production in Rat Anterior Pituitary Cells: an Immunohistochemical Study
- Creator:
- Kus, I., Sarsilmaz, M., Colakoglu, N., Kukner, A., Ozen, O.A., Yilmaz, B., and Kelestimur, H.
- Type:
- article, model:article, and TEXT
- Subject:
- Leptin, Melatonin, Pinealectomy, Anterior Pituitary, and Rat
- Language:
- English
- Description:
- Melatonin, the main hormone of the pineal gland, informs the body about the environmental light and darkness regimen, which in turn contributes to the photoperiodic adaptation of several physiological functions. Leptin, the hormone secreted mainly by adipocytes and some other tissues including the pituitary, informs the brain about the mass of adipose tissue, which plays an important role in energy homeostasis. Melatonin has been shown to decrease circulating leptin levels. It is currently not known whether melatonin has an effect on leptin synthesis in the pituitary. The aim of this study was to immunohistochemically examine the effects of pinealectomy and administration of melatonin on leptin production in the rat anterior pituitary. The pituitary samples obtained from 18 male Wistar rats including sham-pinealectomized, pinealectomized and melatonin-injected pinealectomized groups were immunohistochemically evaluated. Immunostaining of leptin was moderate (3+) in sham-pinealectomized rats, heavy (5+) in pinealectomized rats and low (1+) in melatonin-treated pinealectomized rats, respectively. The present results indicate that pinealectomy induces leptin secretion in anterior pituitary cells, and this increase of leptin synthesis can be prevented by administration of melatonin. Thus, melatonin seems to have both physiological and pharmacological effects on leptin production in the anterior pituitary of male rats.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
13. Plasma Ghrelin Levels in Patients with End-Stage Renal Disease
- Creator:
- Jarkovská, Z., Marek, J. , Rosická, M., Kršek, M., Sulková, S., Haluzík, M., Justová, V. , and Lacinová, Z.
- Type:
- article, model:article, and TEXT
- Subject:
- Ghrelin, Leptin, Soluble leptin receptor, and End-stage renal disease
- Language:
- English
- Description:
- Ghrelin is an acylated peptide stimulating secretion of the growth hormone (GH). It was originally isolated from the rat stomach as an endogenous ligand for the growth hormone secretagogue receptor. Although being predominantly produced by endocrine cells of the gastric fundus, its secretion has been found in various tissues including the kidney. To study the influence of renal failure on plasma ghrelin levels we examined 16 patients with end-stage renal disease (ESRD) receiving hemodialysis (8 men and 8 women) and 19 controls (10 men and 9 women). Both groups were comparable in age and BMI. In all subjects we assessed plasma levels of ghrelin, leptin, soluble leptin receptor, insulin, IGF-I, IGFBP-1, IGFBP-3 and IGFBP-6. Ghrelin levels were significantly higher in the group of dialyzed patients (4.49±0.74 vs. 1.79±0.15 ng/ml; p<0.001). These patients had significantly higher levels of GH, IGFBP-1, IGFBP-6, leptin and percentage of body fat (p<0.05). In the group of patients with ESRD plasma ghrelin levels positively correlated with IGFBP-1 (p<0.01). In the control group, ghrelin positively correlated with GH concentrations (p<0.01) and negatively correlated with the levels of insulin and creatinine (p<0.05). In conclusion, patients with ESRD have higher ghrelin concentrations, which might be caused by a decreased excretion/metabolism of ghrelin in the kidney during renal failure.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14. Plasma Levels of Total and Active Ghrelin in Acromegaly and Growth Hormone Deficiency
- Creator:
- Jarkovská, Z., Rosická, M., Marek, J., Hána, V., Weiss, V., Justová, V., Lacinová, Z., Haluzík, and Kršek, M.
- Type:
- article, model:article, and TEXT
- Subject:
- Total ghrelin, Active ghrelin, Leptin, Acromegaly, and Growth hormone deficiency
- Language:
- English
- Description:
- Ghrelin is an endogenous growth hormone (GH) secretagogue recently isolated from the stomach. Although it possesses a strong GH releasing activity in vitro and in vivo, its physiological significance in endogenous GH secretion remains unclear. The aim of this study was to characterize plasma ghrelin levels in acromegaly and growth hormone deficiency (GHD). We investigated plasma total and active ghrelin in 21 patients with acromegaly, 9 patients with GHD and 24 age-, sex- and BMI-matched controls. In all subjects, we further assessed the concentrations of leptin, soluble leptin receptor, insulin, IGF-I, free IGF-I and IGFBP-1, 2, 3 and 6. Patients with acromegaly and GHD as well as control subjects showed similar levels of total ghrelin (controls 2.004±0.18 ng/ml, acromegalics 1.755±0.16 ng/ml, p=0.31, GHD patients 1.704±0.17 ng/ml, p=0.35) and active ghrelin (controls 0.057±0.01 ng/ml, acromegalics 0.047±0.01 ng/ml, p=0.29, GHD patients 0.062±0.01 ng/ml, p=0.73). In acromegalic patients plasma total ghrelin values correlated negatively with IGF-I (p<0.05), in GHD patients active ghrelin correlated with IGF-I positively (p<0.05). In the control group, total ghrelin correlated positively with IGFBP-2 (p<0.05) and negatively with active ghrelin (p=0.05), BMI (p<0.05), WHR (p<0.05), insulin (p=0.01) and IGF-I (p=0.05). Plasma active ghrelin correlated positively with IGFBP-3 (p=0.005) but negatively with total ghrelin and free IGF-I (p=0.01). In conclusion, all groups of the tested subjects showed similar plasma levels of total and active ghrelin. In acromegaly and growth hormone deficiency plasma ghrelin does not seem to be significantly affected by changes in GH secretion.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
15. Serum Leptin Concentrations in Patients with Combined Hyperlididemia: Relationships to Serum Lipids and Lipoproteins
- Creator:
- Haluzík, M., Fiedler, J., Nedvídková, J., and Češka, R.
- Type:
- article, model:article, and TEXT
- Subject:
- Leptin, Cholesterol, Triglycerides, HDL, LDL, and Body mass index
- Language:
- English
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16. The effect of neonatal maternal stress on plasma levels of adrenocorticotropic hormone, corticosterone, leptin, and ghrelin in adult male rats exposed to acute heterotypic stressor
- Creator:
- Holubová, A., Štofková, A., Jurčovičová, J., and Šlamberová, R.
- Type:
- article, model:article, and TEXT
- Subject:
- Stress, ACTH, Corticosterone, Leptin, and Ghrelin
- Language:
- English
- Description:
- Activation of the hypothalamic-pituitary-adrenal (HPA) axis is important for maintenance of homeostasis during stress. Recent studies have shown a connection between the HPA axis and adipose tissue. The present study investigated the effect of acute heterotypic stress on plasma levels of adrenocorticotropic hormone (ACTH), corticosterone (CORT), leptin, and ghrelin in adult male rats with respect to neonatal maternal social and physical stressors. Thirty rat mothers and sixty of their male progeny were used. Pups were divided into three groups: unstressed control (C), stressed by maternal social stressor (S), stressed by maternal social and physical stressors (SW). Levels of hormones were measured in adult male progeny following an acute swimming stress (10min) or no stress. ELISA immunoassay was used to measured hormones. The ACTH and CORT levels were significantly increased in all groups of adult progeny after acute stress; however, CORT levels were significantly lower in both neonatally stressed groups compared to controls. After acute stress, plasma leptin levels were decreased in the C and SW groups but increased in the S group. The data suggest that long-term neonatal stressors lead to lower sensitivity of ACTH receptors in the adrenal cortex, which could be a sign of stress adaptation in adulthood. Acute stress in adult male rats changes plasma levels of leptin differently relative to social or physical neonatal stressors.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
17. The Influence of Very-Low-Calorie Diet on Serum Leptin, Soluble Leptin Receptor, Adiponectin and Resistin Levels in Obese Women
- Creator:
- Anderlová, K., Křemen, J., Doležalová, R., Housová, J., Haluzíková, D., Kunešová, M., and Haluzík, M.
- Type:
- article, model:article, and TEXT
- Subject:
- Obesity, Insulin sensitivity, Very-low-calorie diet, Leptin, Adiponectin, and Resistin
- Language:
- English
- Description:
- The aim of our study was to determine whether adipocyte-derived hormones leptin, adiponectin and resistin contribute to the improvement of insulin sensitivity after very-low calorie diet (VLCD). Therefore, serum levels of these hormones were measured in fourteen obese females before and after three weeks VLCD and in seventeen age- and sex-matched healthy controls. Body mass index, HOMA index, serum insulin and leptin levels in obese women before VLCD were significantly higher than in control group (BMI 48.01±2.02 vs. 21.38±0.42 kg/m2, HOMA 10.72±2.03 vs. 4.69±0.42, insulin 38.63±5.10 vs. 18.76±1.90 μIU/ml, leptin 77.87±8.98 vs. 8.82±1.52 ng/ml). In contrast, serum adiponectin and soluble leptin receptors levels were significantly lower in obese women before VLCD than in the control group. No differences were found in serum glucose and resistin levels between the obese group before VLCD and the control group. VLCD significantly decreased BMI, HOMA index, serum glucose, insulin and leptin levels and increased soluble leptin receptor levels. The changes in serum adiponectin and resistin levels in obese women after VLCD did not reach statistical significance. We conclude that leptin and soluble leptin receptor levels were affected by VLCD while adiponectin and resistin concentrations were not. Therefore, other mechanisms rather than changes in the endocrine function of the adipose tissue are probably involved in the VLCD-induced improvement of insulin sensitivity.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18. The postoperative stress response and its reflection in cytokine network and leptin plasma levels
- Creator:
- Chachkhiani, I., Gürlich, R. , Maruna, P., Fraško, R., and Lindner, J.
- Type:
- article, model:article, and TEXT
- Subject:
- Cytokines, Leptin, Systemic inflammatory reaction, and Surgical stress
- Language:
- English
- Description:
- The objective of the present report was to clarify the postoperative stress response of some inflammatory markers, namely of proinflammatory cytokines and leptin levels during uncomplicated postoperative periods. The results were compared with the dynamics of these parameters during intraabdominal sepsis. We followed 20 patients after a planned resection of colorectal cancer in stage Ib-IV with uncomplicated healing and 13 obese men after laparoscopic non- adjustable gastric banding. These were compared to 12 patients with proven postoperative sepsis. The control group consisted of 18 healthy men. The observed parameters included serum levels of cytokines, tumor necrosis factor-α(TNFα), interleukin-1β (IL-1β), interleukin-1 receptor antagonist (IL-1ra), IL-6, IL-8, soluble receptor of interleukin-2 (sIL-2R) and leptin. It was found that during the first 24 h after resection there was a significant increase in the serum concentration of IL-6 up to 1125±240 ng/l, which declined within the next 48-72 h. Serum concentration of TNF α was highest 18-24 h after resection (205±22 ng/l) and after banding (184±77 ng/l). IL-1β had a stable serum concentration without significant elevation. Serum concentration of IL-8 after resection rose to 520±200 ng/l after 36-48 h. Maximal cytokine levels after gastric banding were quantitatively lower (IL-6 414±240 ng/l, TNFα 184±77 ng/l) than after resection. We found significant elevation of plasma leptin concentration (32±10 ng/ml) 24 h after banding compared with preoperative values (18±5 ng/ml, p<0.05). Leptin levels 48 and 72 h after banding rapidly returned to the level before operation. During abdominal surgery leptin shows to be an acute phase reactant. Proinflammatory cytokines can be main regulatory factors of leptin during this period. Significant correlation between leptin and TNFα (similarly demonstrated by other authors in models of bacterial inflammation) indicates that TNFα can be the crucial regulator of leptin generation in the early postoperative period. On the basis of our results we recommend to observe IL-6 and IL-8 at 24-72 h after the surgery in patients with a high risk of early postoperative septic complications.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public