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Biomedical subjects

F Pirnay

Publications and source records attributed to F Pirnay.

At least 55 records · Page 3Linked to original sources
PubMed1978

Effect of glucose on plasma glucagon and free fatty acids during prolonged exercise.

The effects of glucose ingestion on the changes in blood glucose, FFA, insulin and glucagon levels induced by a prolonged exercise at about 50% of maximal oxygen uptake were investigated. Healthy volunteers were submitted to the following procedures: 1. a control test at rest consisting of the ingestion of 100 g glucose, 2. an exercise test without, or 3. with ingestion of 100 g of glucose. Exercise without glucose induced a progressive decrease in blood glucose and plasma insulin; plasma glucagon rose significantly from the 60th min onward (+45 pg/ml), the maximal increase being recorded during the 4th h of exercise (+135 pg/ml); plasma FFA rose significantly from the 60th min onward and reached their maximal values during the 4th h of exercise (2177 +/- 144 muEq/l, m +/- SE). Exercise with glucose ingestion blunted almost completely the normal insulin response to glucose. Under these conditions, exercise did not increase plasma glucagon before the 210th min; similarly, the exercise-induced increase in plasma FFA was markedly delayed and reduced by about 60%. It is suggested that glucose availability reduces exercise-induced glucagon secretion and, possibly consequently, FFA mobilization.

Administration, Oral↗
PubMed1978

Oxidation of an exogenous glucose load using naturally labelled 13C-glucose. Effect of butylbiguanide therapy in obese mildly diabetic subjects.

The effect of a 14 day-administration of butylbiguanide was investigated in a group of 10 obese patients with mild-to-moderate glucose intolerance. Glucose tolerance was significantly improved, while fasting blood glucose and plasma levels of free fatty acids, insulin and glucagon remained unchanged. The estimation of the amount of the oral glucose load oxidized into CO2 was performed by means of a recently described procedure using "naturally labelled 13C-glucose" as tracer. The curves depicting the oxidation of the exogenous glucose load were similar in shape and magnitude before and after administration of the biguanide; in the latter case, however, slightly higher rates of oxidation of exogenous glucose were recorded during the 2nd, 3rd and 4th hours of the test. These data do not provide evidence that the biguanide-induced improvement in glucose tolerance in patients with mild-to-moderate glucose intolerance is associated with any inhibiting or delaying effect of this type of drug on intestinal absorption (and subsequent oxidation) of the exogenous glucose load. On the contrary, a slight, but statistically significant, increase in the oxidation of exogenous glucose has been observed after butylbiguanide.

Adult↗
PubMed1977

Influence of water temperature on thermal, circulatory and respiratory responses to muscular work.

Different muscular exercises have been executed on a bicycle ergometer during immersion in water, the temperature of which varied between 20 and 40 degrees C. During submaximal works, O2 consumption was not modified by the temperature of the water. On the other hand, body temperature (rectal and muscular) are clearly influenced by environment. The temperature of the quadriceps varies from 37.7-38.5 degrees C when the bath temperature rises from 20-40 degrees C during the same work intensity corresponding to 1/3 of the individual maximal work capacity. The rectal temperature was always lower about 0.5 degrees C. Ventilation and heart rate underwent modifications which were significantly accentuated in hot water. Maximal O2 consumption does not reach its highest level in cold water. The low muscular temperature observed in these conditions seems to limit the aerobic metabolism and the working of the muscles. Maximal O2 consumption then rises in parallel with the increase in bath temperature and in body temperatures. In very hot water however (40 degrees C), when rectal temperature rises unduly, the circulatory demand linked to thermolysis becomes excessive, and maximal O2 consumption decreases.

Adult↗
PubMed1977

Effect of glucose ingestion on energy substrate utilization during prolonged muscular exercise.

The distribution of substrates utilized during prolonged exercise was investigated in normal human volunteers with an without ingestion of 100 g exogenous glucose. The energy provided by protein oxidation was derived from urinary nitrogen excretion and the total energy provided by carbohydrates and lipids was calculated from respiratory quotient (RQ) determinations. The contribution of exogenous glucose to the energy supply was determined by an original procedure using "naturally labeled 13C-glucose" as metabolic tracer. Protein oxidation provided between 1 and 2% of the total energy requirement; this amount was not affected by glucose ingestion. In the absence of exogenous glucose ingestion, carbohydrate were progressively replaced by lipids as source of energy. Exogenous glucose contributed markedly to total carbohydrate oxidation and decreased the percentage of energy derived from lipids. In addition, ingestion of exogenous glucose resulted in a significant economy of endogenous carbohydrates and permitted to prolong the duration of exercise.

Adult↗
PubMed1976

Quantitative evaluation of the oxidation of an exogenous glucose load using naturally labeled 13C-glucose.

Maize glucose was used as a natural tracer for studies of metabolism. It is richer in 13C than common vegetables and foods derived from these, and the C02 formed from it is consequently richer in 13C than the CO2 expired by man fed on a diet of common vegetables. The quantitative results, obtained by measurement of delta 13C of the expired CO2 and of VCO2 during the oxidation of an exogenous glucose load (about 100 g) in eight normal subjects over 7 hr, have shown a consumption of 28.64 +/- 1.44 g of glucose (mean +/- SEM), which represents about 30% of the load given. A comparison is made with the results obtained from other methods and the originality and usefulness of this new quantitative procedure is outlined.

Adult↗