The FTO gene variants are the most important genetic determinants of body weight and obesity known so far, but the mechanism of their effect remain s unclear. We have analyzed FTO rs17817449 variant (G>T in first intron) in 6024 adults aged 45-69 years to assess the potential mediating role of diet and physical activity. Diet was assessed by a 140-item food frequency questionnaire. Physical activity was measured by hours spent during a typical week by sport, walking and other activities outside of work requiring heavy and medium physical activity. Basal metabolic rate was calculated according Schofield formula. The FTO variant was significantly associated with body mass index (means in GG, GT and TT ca rriers were 28.7, 28.2 and 27.8 kg/m 2 , p<0.001) and basal metabolic rate (BMR) (means in GG, GT and TT were 1603, 1588 and 1576 kcal per day, respectively, p<0.008) but it was not associated with physical activity, total energy intake or with energy intakes from fat, carbohydrates, proteins or alcohol. Results were essentially similar in men and women and the adjustment for physical activity or dietary energy intake did not reduce the effect of the FTO polymorphism. Means of BMR per kg of body weight was lowest in GG carriers (20.09, 20.21 for GT and 20.30 for TT, p< 0.006) and this effect was more pronounced in females. These results suggest that the effect of the FTO rs17817449 variant on BMI in Caucasian adults is not mediated by energy intake or physical activity, but some effect on BMR per kg of body weight is possible., J. A. Hubáček ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Metabolic rate, body temperature, and thermal conductance were determined in the greater long-tailed hamster (Cricetulus triton) at a temperature range of 5-36 °C. Oxygen consumption was measured by using a closed circuit respirometer. The thermal neutral zone was 39-34 °C. Within a temperature range of 5-31 °C hamsters could maintain a stable body temperature at a mean of 36.7±0.1 °C. Mean basal metabolic rate within thermal neutrality was 1.23±0.02 ml O2/g.h. Total thermal conductance was maintained within a temperature range of 5-15 °C (mean = 0.12±0.00 ml O2/g.h °C). The ecophysiological properties of the greater long-tailed hamster were: (1) a higher metabolic rate than predicted by the allometric scaling equation for eutherian mammals, but lower than that predicted for all rodents and slightly higher than predicted for cricetid rodents; (2) the body temperature was relatively low; (3) thermal conductance was relatively higher than predicted on the basis of body weight. All these characteristics are closely related to the species' life style (i.e. a burrowing, solitary, nocturnal species that feeds mainly on crop seeds and a small fraction of young crop shoots and insects). Greater long-tailed hamsters are primarily distributed in the northern Yangtse River area of China and cannot survive in extremely dr and alpine areas. We propose that the ecophysiological characteristics of the species might constrain its distribution and range extension into extreme deserts, high altitudes and cold areas.