[Changes in serum and adipose tissue fatty acid composition after low calorie diet with respect to dietary fat content in obese]. / Zmeny slození mastných kyselin v séru a tukové tkáni v závislosti na obsahu tuku v nízkoenergetické diete.

BACKGROUND: Recently, a new attention has been paid to beneficial effects of high-fat diet on the body weight reduction and metabolic profile in obese subjects. In this study we compared the effects of two hypocaloric diets with different proportion of fat on fatty acid composition (FA) in blood and adipose tissue (AT). METHODS AND RESULTS: Forty-four obese subjects were submitted to 10 weeks' low-calorie diet. Subjects were randomized into low-fat diet (LFD) (20-25% of energy content) and high-fat diet groups (HFD) (40-45%). Before and at the end of the intervention, samples of blood and subcutaneous AT were taken for the analysis of fatty acid composition. The diet-induced body weight and fat mass reduction were not different between the two diets. Plasma triacylglycerols (TAG) were reduced during HFD only. Both diets reduced proportion of n-3 polyunsaturated fatty acids in AT and of saturated fatty acid in blood TAG, with no difference between the diets. HFD induced a higher increase of monounsaturated fatty acids in blood TAG. No other diet-induced changes were found in proportion of major classes of fatty acids. In respect to individual fatty acids, the diets induced a number of changes in AT and blood, the changes, however, not being different between the diets. CONCLUSION: Hypocaloric diets induce a number of changes in fatty acid composition in blood and adipose tissue, with little differences in respect to the proportion of fat in the diet. The results suggest the diet-induced changes in fatty acid composition are controlled by the calorie deficit of the diet and the proportion of dietary fat plays a minor role.

Effect of endurance training on adrenergic control of lipolysis in adipose tissue of obese women.

The effect of a 12-wk training program on sc abdominal adipose tissue (SCAAT) was studied in 11 obese women. Before and after the training, biopsies of SCAAT were performed for mRNA levels determination. Using the microdialysis method, involvement of alpha(2)- and beta-adrenergic receptor (ARs) in the control of lipolysis in SCAAT was studied using local perfusion of epinephrine alone or supplemented with phentolamine, an alpha(2)-AR antagonist. In addition, the variation in dialysate glycerol concentrations during exercise (50% peak oxygen consumption at 40 min) in a probe perfused with Ringer's solution was compared with that obtained in a probe perfused with Ringer's solution plus phentolamine. Training did not promote changes in the expression of key genes of the lipolytic pathway. The epinephrine-induced rise in the dialysate glycerol concentration was identical before and after training and was similarly potentiated by phentolamine. During exercise, the potentiating effect of phentolamine on the glycerol response was apparent before, but not after, training. The exercise-induced increase in plasma norepinephrine was lower after training (P = 0.04). In conclusion, training did not modify either the expression of genes involved in the control of lipolysis or alpha(2)- and beta-ARs in situ sensitivity to epinephrine in SCAAT. Training reduced the antilipolytic action of catecholamines mediated by alpha(2)-ARs during exercise, probably due to a reduction of exercise-induced catecholamine increase.

[Effect of dynamic strength training on insulin sensitivity in men with insulin resistance]. / Vliv silove-dynamického tréninku na inzulínovou senzitivitu u inzulínorezistentních muzu.

BACKGROUND: Physical activity is generally accepted as a part of the nonpharmacological therapy of the insulin resistance. Endurance training is generally recommended as an appropriate approach. The aim of this study was to assess the effect of three-month dynamic strength training on the insulin sensitivity in middle-aged men with insulin resistance. METHODS AND RESULTS: 10 men (5 obese non diabetics and 5 overweight patients with diabetes mellitus type 2 (age 51.36+/-7.25 years, average weight 110.16+/-13.56 kg and BMI 33.22+/-3.52 kg/m2 underwent a three-month dynamic strength training at the level of 60 to 70 % of their maximum muscle strength (one-repetition maximum 1-RM). Insulin sensitivity was determined using the hyperinsulinic euglycemic clamp before and after the training period. Training promoted to increase the muscle strength (p<0.001). It did not induce changes in body weight, body composition and maximum aerobic capacity. The training induced an increase in insulin sensitivity (glucose disposal M: 3.0 vs 4.0 M - mg/min/kg, p<0,01). CONCLUSIONS: Dynamic strength training improves insulin sensitivity in men with insulin resistance independently on weight loss or increase in aerobic capacity. Our results suggest that the dynamic strength training is an appropriate physical activity for management of the insulin resistance.