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Metabolic effects of chronic metformin administration in obese mice depending on the composition of high-fat diet
Roubalová, Jana ; Rossmeisl, Martin (advisor) ; Vybíral, Stanislav (referee)
Obesity leads to many severe metabolic disorders, e.g. dyslipidemia, insulin resistance, ectopic fat accumulation in the liver and skeletal muscles, non-alcoholic fatty liver disease and finally diabetes mellitus type 2. Metformin (1,1-dimethylbiguanide) is the most favored medicament for the treatment and prevention of these disorders. It stimulates cellular glucose uptake and normalizes blood levels of lipid metabolites without triggering insulin secretion. Research on insulin resistance and diabetes is often realized through developing diet- induced obesity in laboratory animals. The aim of this project is to compare metabolic effects of two different high-fat diets named HFD and HSD. The HFD diet consists chiefly of n-6 polyunsaturated fatty acids (corn oil) and starch (100% glucose). The HSD diet contains mainly saturated fatty acids (lard) and sucrose (50% glucose and 50% fructose). I also studied metabolic effects of metformin by adding it continuously to the drinking water given to obese mice fed with the HFD or the HSD diet. Methods: Intraperitoneal glucose tolerance test (IPGTT), blood and tissue levels of lipid metabolites assessment, radio-immunological assessment of blood levels of insulin, assessment of AMPK activity in liver by western blotting. Results: Increased consumption of the...
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Microclimatic characteristics of natural and synanthropic roosts of dendrophilous and crevice-dwelling bats.
Nodžáková, Kateřina ; Vybíral, Stanislav (advisor) ; Benda, Petr (referee)
This study has tested microclimatic characteristics of natural and synanthropic roosts in the Trebonsko Biosphere Reserve - an important area in South Bohemia. Using a data logger, we measured the temperature in cavities used and unused by bats and compared them with temperature in artificial roost - window shutter and limekiln. Our results provide direct evidence that limekiln and cavities are occupied by different species of bats in comparison with window shutter and we contend that selecting microclimatic conditions of roosts are species-specific. Using limekiln may be more advantageous to bats than tree cavities, especially during pregnancy and lactation, since it provides suitable microclimate for roosting. This may be one of the factors associated with aggregation of maternity colonies during gestation period. Further we measured metabolic rate (oxygen consumption) in various temperatures of surroundings. Following species were taken into experiments: Eptesicus serotinus and Nyctalus noctula. The temperature interval was 26 - 43 řC. Our results confirmed different demands on microclimatic conditions in both species. We hypothesize that high roost temperatures within the thermal neutral zone enables bats to maintain body temperature passively thereby minimize energetic costs.
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Peptide hormones affecting the food intake and their analogs as potential drugs for treatment of obesity
Nagelová, Veronika ; Maletínská, Lenka (advisor) ; Vybíral, Stanislav (referee)
Obesity is nowadays a major global health problem. Every year amount of obese (BMI > 30 kg . m-2 ) and overweight (BMI > 25 kg . m-2 ) people increases. Obesity is not just a cosmetic problem, but it leads to many serious health complications, particularly cardiovascular diseases, metabolic diseases etc. We can define obesity as an excessive amount of body fat. The development of obesity is often influenced by energy intake, which overrides the energy expenditure. Many studies are currently describe the influence of various substances that could potentially act as antiobesity drugs. Peptide hormones, which are engaged in this work, can be divided to the long-term (leptin, insulin, ghrelin) and short-term (e.g. cholecystokinin, glucagon like peptide 1, peptide YY, CART peptides, melanocortin system, neuropeptide Y and melanin concentrating hormone) acting. Peptides can be also divided according to their effect on food intake to the anorexigenic and orexigenic. Anorexigenic peptides reduce food intake, orexigenic do the reverse.
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