Effect of a three-day interruption of exercise-training on resting metabolic rate and glucose-induced thermogenesis in training individuals.

Exercise-training has been shown to influence resting components of energy expenditure in lean and obese individuals. Moreover, experimental data suggest that the effect of training on these components could represent an acute effect of exercise. In this regard, the present study was undertaken to determine whether resting metabolic rate (RMR) and glucose-induced thermogenesis (GIT) could be modified depending on the delay elapsing between the last exercise session of a training program and calorimetric measurements.

Effects of vitamin B12 supplementation on choline acetyltransferase activity in cat brain.

Vitamin B12 was daily supplemented to a semi-purified casein diet and given per os during 17 consecutive days to cats in a dosage of 25 micrograms/kg every morning at the meal time. The specific choline acetyltransferase activity, measured in several structures in cat brain, was significantly increased in the hypothalamus, piriform lobe, hippocampus, pons and pons raphe nuclei and significantly decreased in the medulla raphe nuclei, respectively. These results demonstrate for the first time that vitamin B12 involved as coenzyme in biochemical reactions related to the liberation of methyl synthesis synthesis through the bioavailability of choline, the enzyme substrate of choline acetyltransferase.

Effects of fenfluramine in hypertriglyceridemic obese subjects.

Forty-four hyperlipidemic obese subjects, selected because of their refractoriness towards diet-therapy, participated voluntarily in a 12-week double-blind study comparing the effects of a long-acting fenfluramine (Ponderal Pacaps) to those of a placebo. In spite of no dietetic intervention, a significant 3-kg weight loss (P less than 0.001) was observed in the fenfluramine-treated group, accompanied by a significant improvement of most atherogenic parameters of plasma lipoproteins.

Sensitivity to overfeeding: the Quebec experiment with identical twins.

The role of the genotype in the response to short-term overfeeding was assessed by submitted six pairs of male monozygotic twins to a 4.2 MJ (1000 kcal) per day energy intake surplus for a period of 22 consecutive days. Individual differences in fat mass and fat-free mass gains were observed in response to overfeeding but they were not randomly distributed.

Genotype-influenced changes in serum HDL cholesterol after short-term overfeeding in man: association with plasma insulin and triglyceride levels.

Six pairs of male monozygotic (MZ) twins were submitted to a 22-day overfeeding period during which they ingested a daily surplus of 1,000 kcal above their individual daily energy needs in the form of a mixed diet. Serum lipids, lipoproteins, and apoprotein A and B concentrations were measured before and after the overfeeding period. Percentage of body fat, fasting plasma glucose, and insulin levels as well as plasma glucose and insulin concentrations after a glucose challenge were also measured before and after overfeeding.

Acute diabetes mellitus does not impair survival rate in rats submitted to left coronary artery ligation.

This study was designed to assess whether the acute metabolic disturbances associated with diabetes mellitus of three-days duration could influence the survival of rats submitted to experimental myocardial infarction. Diabetes was induced with streptozotocin (50 mg/kg) in male Wistar rats and three days later left coronary artery ligation was performed in both control (n = 34) and diabetic (n = 31) animals. Diabetic rats had significant alterations in plasma levels of glucose (424 +/- 6 vs 143 +/- 3 mg/dL; p less than 0.

Heredity and overfeeding-induced changes in submaximal exercise VO2.

The present study investigated the role of heredity in determining changes in the energy cost of submaximal exercise in response to short-term overfeeding. Six pairs of monozygotic twins were subjected to a 1,000 kcal/day surplus for 22 days with careful experimental controls over food intake and physical activities. O2 consumption (VO2) was measured during a submaximal treadmill exercise test 165 min postprandially before and the morning after the overfeeding protocol.

Is the response of plasma glucose and insulin to short-term exercise-training genetically determined?

Six male monozygotic (MZ) twin pairs participated in the present study which was undertaken to assess the contribution of heredity to changes in plasma glucose and insulin in response to exercise-training. This group was submitted to a vigorous ergocycle exercise program inducing a surplus in energy expenditure of 1000 kcal/day over habitual energy expenditure during 22 consecutive days. An oral glucose tolerance test (OGTT, 75 g glucose) was performed before and about 16 hours after the experimental period.

The role of body fat in insulin sensitivity of endurance athletes.

The purpose of the study was to assess the role of adiposity in the enhanced insulin sensitivity observed in endurance athletes (EA). An oral glucose tolerance test (75 g glucose) was administered to nine EA and to 23 sedentary subjects (SS). Two different strategies were used to investigate the problem.

Heredity and changes in hormones and metabolic rates with short-term training.

The purpose of this experiment was to assess the effects of a 22-day training program on resting metabolic rate (RMR), thermic effect of a meal (TEM), and associated hormonal changes. Six pairs of male monozygotic twins were submitted to a 22-day ergocycle exercise program designed to induce a deficit in energy balance of 4.2 MJ per day.

Increased mortality rate in diabetic rats submitted to acute experimental myocardial infarction.

Diabetes mellitus is well known to increase the death rate after acute myocardial infarction in humans. The mechanisms of this adverse effect of diabetes, however, remain unknown. In the present study an animal model was developed in which the influence of diabetes on the survival rate after acute myocardial infarction could be studied in more detail.

Genotype dependency of the thermic effect of a meal and associated hormonal changes following short-term overfeeding.

The purpose of this experiment was to assess the effects of short-term overfeeding (mixed diet) on the thermic effect of a meal (TEM) and associated hormonal changes and to investigate the role of the genotype in the observed changes. Six pairs of male sedentary monozygotic (MZ) twins consumed an extra 1,000 kcal per day over their individual level of energy expenditure while maintaining a sedentary existence. Resting metabolic rate (RMR) and TEM following a 4.

Effect of physical training on norepinephrine turnover in tissues of normal and diabetic rats.

This study was designed to examine the influence of physical training on the norepinephrine turnover rate in heart, pancreas, liver, and gastrocnemius muscles of normal and diabetic male rats at rest. Diabetes was induced with the IV injection of streptozotocin (45 mg/kg) and physical training was done on a treadmill according to a ten-week program. Norepinephrine turnover rate of tissues was estimated by following over time the decay in the specific activity of norepinephrine after a single IV bolus of tritiated norepinephrine (30 microCi/kg).

Diminished glucagon response to epinephrine in physically trained diabetic rats.

The effect of physical training on glucose, insulin, and glucagon response to epinephrine was assessed in normal and diabetic rats. Male Wistar rats were injected with streptozocin (STZ, 45 mg/kg) and those presenting 1 wk later a blood glucose value between 250 and 400 mg/dl were retained in the protocol and randomly assigned to a sedentary or trained group. Similar studies were conducted in control animals.

Effect of streptozotocin-induced diabetes on insulin binding parameters in adult rat testis.

Insulin binding parameters have been measured in testicular membranes of streptozotocin diabetic male rats. Insulin binding decrease was ascribed to the well-known depressing effect of diabetes mellitus on circulating luteinizing hormone (LH). Because both LH and insulin receptors are modulated by pituitary LH and because of their reduction in testes of diabetic rats, we conclude that Leydig cell dysfunction is a secondary disorder associated with this complex metabolic condition.

Hyperglycemic effect of high doses of dobutamine in the rat: studies of insulin and glucagon secretion.

The influence of dobutamine on glucoregulation has been assessed in the rat during and after an intravenous infusion given at the following doses: 0, 0.1, 1.0, 10, 100, and 1000 micrograms X kg-1 X min-1.

Contribution of postexercise increment in glucose storage to variations in glucose-induced thermogenesis in endurance athletes.

The present study was undertaken to evaluate the contribution of an increment in glucose storage to the reduced glucose-induced thermogenesis (GIT) characterizing endurance-trained individuals. For that purpose, glucose storage and GIT were determined during an oral glucose tolerance test (OGTT) in eight elite endurance athletes exercising between 6 and 16 h/week. Their values were compared with those obtained in five nontrained subjects submitted to two OGTT, i.

Plasma, adrenal, and heart catecholamines in physically trained normal and diabetic rats.

This study was designed to evaluate the possibility that the enhanced insulin sensitivity of physically trained normal and diabetic rats is due to adaptive changes in the adrenergic system. Mild diabetes mellitus was induced in male Wistar rats with streptozocin (STZ, 45 mg/kg i.v.

Contribution of the exercise-induced increment in glucose storage to the increased insulin sensitivity of endurance athletes.

The present study was designed to evaluate the contribution of the exercise-induced increment in glucose storage to the increased insulin sensitivity characterizing endurance athletes. Plasma glucose and insulin were measured during an oral glucose tolerance test (OGTT) in six endurance athletes. Glucose storage and lipid oxidation during this test were also determined using indirect calorimetry.

Decrease in ventricular beta-adrenergic receptors in trained diabetic rats.

The effects of physical training on beta-adrenergic receptors were evaluated in heart ventricular tissue of diabetic rats. Mild diabetes mellitus was induced in rats with streptozotocin (45 mg/kg, iv). They were then submitted to a progressive 10-week running programme on a treadmill.

Functional hypoglycemia: facts and fancies.

When blood glucose decreases below a given threshold, symptoms of cerebral dysfunction and/or adrenergic hyperactivity appear. If this occurs postprandially in otherwise normal subjects, a diagnosis of reactive or functional hypoglycemia may be proposed. However, these symptoms are not specific, and they should coincide with low blood glucose values and be rapidly relieved by glucose ingestion before a diagnosis of hypoglycemia is confirmed.

Daily variations of plasma glucose and insulin in physically-trained and sedentary subjects.

The variations in plasma glucose and insulin levels were measured at 30-minute intervals throughout the day in physically trained and in sedentary subjects. The subjects exercised for 75 minutes at 65% of VO2max in the first experiment and refrained from heavy exercise in the second experiment. In all situations the physically trained subjects overall had lower plasma glucose and insulin levels than the nontrained subjects.

Long-term changes in the diabetic state induced by different doses of streptozotocin in rats.

The long-term effects of different doses (0, 25, 35, 45, 55, 65 and 100 mg/kg) of streptozotocin (STZ) in male Wistar rats had been followed over a 16 week period. The weight-gain curve and the epididymal fat pad weight were significantly different (P less than 0.05) from control after 1 week with the 65 and 100 mg/kg doses and after 4 weeks with the 45 and 55 mg/kg doses; there were no significant changes with the 25 and 35 mg/kg doses even after 16 weeks.

The influence of high carbohydrate diet on plasma glucose and insulin of trained subjects.

In previous studies we have shown that when endurance athletes refrain from daily exercise for three days, they rapidly loose their enhanced insulin sensitivity. This finding suggests that a precompetitive high carbohydrate diet with reduced training might alter plasma glucose and insulin regulation. To test this hypothesis, six long distance runners were recruited to participate in a five-day experiment.

Effects of physical training on beta-adrenergic receptors in rat myocardial tissue.

A diminished sympathetic activity has been related to training bradycardia seen at rest and during exercise. In order to evaluate if changes in heart adrenergic receptors can be one of the mechanisms by which the sympathetic responsiveness could be decreased by physical training, the number and affinity of beta-adrenergic receptors were determined in heart ventricular tissue of rats submitted to a 10-week running programme. Binding studies were done at different concentrations of (-)[3H] dihydroalprenolol (DHA) (0.