Obesity in T1DM patients is associated with the components of metabolic syndrome. The influence of controlled fasting and low calorie diet (LCD) on insulin sensitivity and glucose metabolism was studied in 14 obese patients with type 1 diabetes mellitus (T1DM) (42.6±9.4 years, BMI 32.4±2.1 kg m−2). Insulin sensitivity in obese T1DM patients was measured using a hyperinsulinemic-euglycemic clamp before fasting, immediately after 7 days of fasting, and after 21 days of LCD. Glucose oxidation and non-oxidative glucose disposal were measured before and during the clamp by indirect calorimetry. In the control group of 13 of non-obese T1DM patients (36.9±13.9 years, BMI 22.6±2.1 kg m−2), only one hyperinsulinemiceuglycemic clamp was performed. Obese T1DM patients lost 6.1±1.1 kg after fasting and maintained reduction in body weight after 21 days of LCD. Fasting transiently reduced insulinmediated glucose disposal in the clamp (from 9.69±1.48 to 6.78±1.21 mg min−1 kg−1, P<0.001). This was caused by reduced glucose oxidation after the fasting period (from 2.81±0.52 to 0.88±0.98 mg min−1 kg−1, P<0.001). We conclude that one week of fasting transiently decreased insulin-mediated glucose disposal in T1DM patients. This was caused by reduced glucose oxidation., F. Musil, ... [et al.]., and Obsahuje seznam literatury
The aim of the present study was to investigate changes in the activity of branched-chain a-keto acid dehydrogenase (BCKAD) in skeletal muscle and the heart during brief and prolonged starvation. Fed control rats and rats starved for 2, 4 and 6 days were anesthetized with pentobarbital sodium before heart and hindlimb muscles were frozen in situ by liquid nitrogen. Basal (an estimate of in vivo activity) and total (an estimate of enzyme amount) BCKAD activities were determined by measuring the release of 14CO2 from a-keto[1-14C]isocaproate. The activity state of BCKAD complex was calculated as basal activity in percentages of total activity. Both basal and total activities and the activity state of the BCKAD were lower in skeletal muscles than in the heart. In both tissues, starvation for 2 or 4 days caused a decrease in the basal activity and activity state of BCKAD. On the contrary, in the heart and muscles of animals starved for 6 days a marked increase in basal activity and activity state of BCKAD was observed. The total BCKAD activity was increasing gradually during starvation both in muscles and the heart. The increase was significant in muscles on the 4th and 6th day of starvation. The demonstrated changes in BCKAD activity indicate significant alterations in branched-chain amino acid (BCAA) and protein metabolism during starvation. The decreased BCKAD activity in skeletal muscle and heart observed on the 2nd and 4th day of starvation prevents the loss of essential BCAA and is an important factor involved in protein sparing. The increased activity of BCKAD on the 6th day of starvation indicates activated oxidation of BCAA and accelerated protein breakdown., M. Holeček., and Obsahuje bibliografii
The aim of this study was to explore the changes in the adipokines leptin and adiponectin in obese patients with type 1 diabetes mellitus (T1DM) who underwent seven days of fasting and 21 days of low-calorie diet (LCD). The plasma leptin and adiponectin concentrations were measured in 14 obese patients with T1DM at baseline, immediately after 7 days of fasting, and after 21 days of LCD. 13 non-obese patients with T1DM were studied only after an overnight fasting. Bioimpedance technique was used for determination of body composition. Obese T1DM patients lost 6.0 kg (6.0; 6.8) (median, 25 %; 75 %) and decreased their fat tissue after fasting and LCD. Plasma leptin in obese T1DM was significantly higher than in non-obese T1DM patients: 9.10 (5.06; 25.89) vs. 1.71 (1.12; 7.08) μg ∙ l-1 and transiently decreased immediately after fasting: 3.45 μg ∙ l-1 (1.47; 7.00), (P<0.05). Adiponectin/leptin ratio in obese T1DM was significantly lower than in non-obese T1DM patients: 0.67 (0.57; 1.49) vs. 3.50 (2.46; 6.30) ∙ 103 and transiently increased immediately after fasting: 2.22 (1.26; 3.24) ∙ 103, (P<0.05). We conclude that obese patients with T1DM are characterized by hyperleptinemia that is reduced by prolonged fasting, but only slightly affected by low calorie diet., F. Musil, V. Blaha, A. Ticha, R. Hyspler, M. Haluzik, J. Lesna, A. Smahelova, L. Sobotka., and Obsahuje bibliografii
The purpose of this study was to compare the effects of shortterm fasting-induced rapid weight loss with those of slower but equivalent body weight loss induced by daily calorie restriction on muscle protein degradation pathways and muscle protein content. Male Fischer rats were subjected to either 30 % calorie restriction for 2 weeks to slowly decrease body weight (Slow) or 3-day fasting to rapidly decrease body weight by a comparable level of that of the Slow group (Rapid). The final body weights were about 15 % lower in both the Slow and Rapid groups than in the Con group (p<0.001). The total protein content and wet weight of fast-twitch plantaris muscle, but not slow-twitch soleus muscle, were significantly lower in the Rapid group compared with the control rats fed ad libitum. Substantial increases in the expression ratio of autophagosomal membrane proteins (LC3-II/-I ratio) and polyubiquitinated protein concentration, used as biomarkers of autophagy-lysosome and ubiquitinproteasome activities, respectively, were observed in the
plantaris muscle of the Rapid group. Moreover, the LC3-II/-I ratio
and polyubiquitinated protein concentration were negatively correlated with the total protein content and wet weight of plantaris muscle. These results suggest that short-term fastinginduced rapid body weight loss activates autophagy-lysosome and ubiquitin-proteasome systems more strongly than calorie restriction-induced slower weight reduction, resulting in muscular atrophy in fast-twitch muscle.
The long-winged (macropterous) and short-winged (brachypterous) adult males of Pyrrhocoris apterus (L.) from temperate (Czech Republic) and Mediterranean (Israel) populations were analysed for the sexual activity and the functional activity of their accessory glands. The sexual activity of the males reared either under long-day (18L : 6D) or short-day (12L : 12D) conditions was determined by their capability to mate with 5-day-old reproductive females of the brachypterous morph and to fertilize the eggs. The functional activity of accessory glands was characterized by the presence of a specific immuno-marker. Sexual activity of fasting macropterous males from both temperate and Mediterranean populations was almost as high as that observed in the reproductive brachypterous ones. These findings were also confirmed by an immunotest. Contrary to the temperate macropterous males, the feeding arrest in temperate macropterous females was coupled with a non-diapause inhibition of reproduction in spite of long days. A similar kind of difference was observed also in the Mediterranean macropterous bugs reared under short-day conditions. The results showed the sexual difference in reproductive activity of the macropterous morph in P. apterus.
The effect of three-day fasting on cardiac ischemic tolerance was investigated in adult male Wistar rats. Anesthetized open-chest animals (pentobarbitone 60 mg/kg, i.p.) were subjected to 20-min left anterior descending coronary artery occlusion and 3-h reperfusion for infarct size determination. Ventricular arrhythmias were monitored during ischemia and at the beginning (3 min) of reperfusion. Myocardial concentrations of beta-hydroxybutyrate and acetoacetate were measured to assess mitochondrial redox state. Short-term fasting limited the infarct size (48.5±3.3 % of the area at risk) compared to controls (74.3±2.2 %) and reduced the total number of premature ventricular complexes (12.5±5.8) compared to controls (194.9±21.9) as well as the duration of ventricular tachycardia (0.6±0.4 s vs. 18.8±2.5 s) occurring at early reperfusion. Additionally, fasting increased the concentration of beta-hydroxybutyrate and betahydroxybutyrate/acetoacetate ratio (87.8±27.0) compared to controls (7.9±1.7), reflecting altered mitochondrial redox state. It is concluded that three-day fasting effectively protected rat hearts against major endpoints of acute I/R injury. Further studies are needed to find out whether these beneficial effects can be linked to altered mitochondrial redox state resulting from increased ketogenesis., M. Šnorek ... [et al.]., and Obsahuje seznam literatury