The insertion (I) allele of the human angiotensin-converting enzyme (ACE) gene is associated with lower serum and tissue ACE activity, and with greater endurance performance and enhanced mechanical efficiency of trained muscle. We tested the hypothesis that the ACE-I allele may be associated with increased slow-twitch fiber, which is more efficient than fast-twitch fiber in low-velocity contraction, by examining the association between the ACE genotype and skeletal muscle fiber (SMF) types in 41 untrained healthy young volunteer subjects (31 males, 10 females, age 24 +/- 3 years). Skeletal muscle samples were taken from the left vastus lateralis using the needle-biopsy method. Slow-twitch type I fibers and fast-twitch type IIa and IIb fibers were classified histochemically based on staining for myosin adenosine triphosphatase (ATPase) activity at different pH values. Amylase-periodic acid-Schiff staining was used to visualize capillaries around fibers. ACE-II subjects had significantly (p < 0.01) higher percentages of type I fibers (50.1 +/- 13.9%vs 30.5 +/- 13.3%) and lower percentages of type IIb fibers (16.2 +/- 6.6%vs 32.9 +/- 7.4%) than ACE-DD subjects. The linear trends for decreases in type I fibers and increases in type IIb fibers from ACE-II --> ID --> DD genotypes were significant as assessed by an analysis of variance. The ratio of type I:II fibers also differed according to the ACE genotype. A multivariate logistic regression analysis showed that the ACE-I allele had significant additive and recessive (codominant) effects on the increased type I fibers and the ratio of type I:II fibers. No specific pattern of capillarization was observed among the three ACE genotypes. In conclusion, the ACE-I allele was associated with increased type I SMF, which may be a mechanism for the association between the ACE genotype and endurance performance.

SummaryWe investigated the effects of dietary red pepper on the energy metabolism in male subjects. In the first experiment, after having a standardized dinner on the previous evening, the subjects consumed a breakfast (650kcal) either with or without 10g of red pepper. For 150 min after the meal, they took a rest and their expired gas was collected. During the initial 30min after the meal, the energy expenditure tended to be higher in the red-pepper diet period than in the control diet period. For the remaining 120min, no difference in the energy expenditure was found between the red-pepper diet period and the control diet period. However the carbohydrate oxidation was significantly higher in the red-pepper diet period than in the control diet period while the lipid oxidation was lower in the red-pepper diet period than in the control diet period for 150 min after the meal. In the second experiment, the subjects consumed a breakfast with 10g of red pepper after an oral administration of propranolol or a placebo. The propranolol abolished the increase in energy expenditure during the initial 30min due to the meal containing red pepper. For the remaining 120min, no difference in energy expenditure was found between the propranolol period and the placebo period. These results suggest that an increase in the energy expenditure after the meal containing red pepper appeared only immediately after the meal ingestion and a red-pepper diet increases the carbohydrate oxidation without increasing total energy expenditure for 150min after the meal. And an increase in the energy expenditure immediately after the meal containing

Twelve patients with essential hypertension (WHO stages I-II) were subjected to mild aerobic exercise for 10 to 20 weeks. The time course of changes in the resting blood pressure and multiple hormonal responses (plasma catecholamines, prostaglandin E, renin-angiotensin system, kallikrein-bradykinin system) were monitored. Depressor response of both systolic and diastolic pressures was seen, and after 5 weeks of exercise blood pressure stabilized at a significantly lower level. Adjustment of work load in response to increased physical fitness at the 10th week produced further reduction of blood pressure especially in diastole. After exercise therapy we found significant reductions in plasma catecholamine levels, and increases in levels of plasma prostaglandin E and the urinary excretion of sodium. A reduction in systolic/diastolic (mean) pressures by more than 20/10 (13) mm Hg was seen in 50% of patients after 10 weeks and in 78% after 20 weeks of exercise. Those who achieved effective blood pressure fall after 10 weeks of training (n = 6) were compared with the rest (n = 6). This analysis revealed that the initial value of plasma renin activity of the former was significantly lower than that of the latter. Significant negative correlations (r = -0.78) also were observed between the blood pressure reduction and corresponding initial value of plasma renin activity. These results indicate that exercise therapy is a potent nonpharmacological tool for the treatment of essential hypertension, especially of the low renin type. Both diminished sympathoadrenergic activity and enhancement of prostaglandin mechanisms might be responsible for the falls in arterial pressure.

The effects of dietary hot red pepper on energy metabolism at rest and during exercise were examined in long distance male runners 18-23 yr of age. A standardized meal was given on the evening prior to the experiment. The subjects had a meal (2720 kJ) with or without 10 g of hot red pepper for breakfast. During rest (2.5 h after meal) and exercise (pedaling for 1 h at 150 W, about 60% VO2max, using cycling ergometry), expired gasses and venous blood were collected. The meal with hot red pepper significantly elevated respiratory quotient and blood lactate levels at rest and during exercise. Oxygen consumption at rest was slightly but nonsignificantly higher in the hot red pepper meal at 30 min after the meal. Plasma epinephrine and norepinephrine levels were significantly higher in those who had only hot red pepper at 30 min after the meal. These results suggest that hot red pepper ingestion stimulates carbohydrate oxidation at rest and during exercise.