PubMed Health⌕ Search

Biomedical subjects

J Boillot

Publications and source records attributed to J Boillot.

29 records · Page 2Linked to original sources
PubMed1987

Decreased insulin binding to adipocytes precedes both hyperinsulinemia and decreased insulin binding to erythrocytes in cafeteria-fed rats.

The relationship between food intake, obesity, insulin binding to adipocytes and erythrocytes, plasma insulin and plasma glucose was studied in an animal model of nutritional obesity--'the cafeteria-fed rats'--after 3 days, 10 days, and 3 weeks of cafeteria feeding. The antilipolytic effect of insulin was also studied. The cafeteria-fed rats ate more carbohydrates after 3 days of diet, while from the 10th day, as previously found, they ate about the same amount of carbohydrates but more lipids and increased in weight. Insulin binding to adipocytes started to decrease (P less than 0.05) 10 days after beginning the cafeteria diet despite the absence of hyperinsulinemia. This decrease in insulin binding to adipocytes was accompanied by a decrease in the responsiveness of adipocytes to the antilipolytic effect of insulin. Hyperinsulinemia (P less than 0.01) appeared only after 3 weeks. At the same time, insulin binding to erythrocytes started also to decrease (P less than 0.05). Plasma glucose levels in the cafeteria-fed rats were unchanged when compared to their controls at any time of the study. There was no correlation between body weight, plasma insulin and insulin binding, to adipocytes and to erythrocytes, at any time of the study. Thus it is possible that factors other than hyperinsulinemia could be involved in the decrease in insulin binding to both adipocytes and erythrocytes.

Adipose Tissue↗
PubMed1985

Effects of nifedipine on responses to exercise in normal subjects.

The responses to sublingual nifedipine (20 mg) and placebo were compared in normal subjects during two studies on cycle ergometer [progressive exercise and constant work-load exercise at approximately 60% of maximal O2 consumption (VO2max)]. The use of nifedipine did not modify maximal power, ventilation (VE), VO2, and heart rate (HR) at the end of the multistage progressive exercise (30-W increments every 3 min). Over the 45 min of the constant-load exercise and the ensuing 30-min recovery we observed with nifedipine compared with placebo 1) no differences in VO2, VE, respiratory exchange ratio, and systolic arterial blood pressure; 2) a higher HR (P less than 0.001) and lower diastolic arterial blood pressure (P less than 0.01); 3) a greater and more prolonged rise in norepinephrine (P less than 0.01) and growth hormone (P less than 0.001); 4) no significant differences in epinephrine and insulin and a lesser increase in glucagon during recovery (P less than 0.01); and 5) a lesser fall in blood glucose (P less than 0.01) and greater increase in acetoacetate (P less than 0.001), beta-hydroxybutyrate (P less than 0.05), and blood lactate (P less than 0.001). Our data do not support the hypothesis that nifedipine reduces hormonal secretions in vivo and are best explained by an enhanced secretion of catecholamines compensating for the primary vasodilator effect of nifedipine.

3-Hydroxybutyric Acid↗
PubMed1977

Glucagon secretion induced by natural and artificial amino acids in the perfused rat pancreas.

The glucagon-secreting potency of 22 amino acids was investigated in the rat isolated perfused pancreas. Arginine and the structurally related amino acids were the most potent A2-cell stimulators that induced a biphasic and sustained glucagon release. Dose-response curver were different for L(+) and D(+)arginine, and the suppressor effect of glucose on the response to L(+) arginine was not detected in the presence of D(+) arginine or homoarginine. Citrulline was the only exception among the arginine-related amino acids; it displayed neither stimulatory nor inhibitory potency on glucagon release. The A2-cell response to D(+) amino acids and artificial analogues of arginine is a strong case for the theory of amino acid receptors' triggering the release of the hormone before (or in the absence of) further metabolism. The prominent rank of arginine and ornithine amont stimulatory amino acids and some other physiologic evidence suggest that A2-cell may play a regulatory role in the metabolsm of ammonia by the liver.

Amino Acids↗
PubMedDate not supplied

Fructose is as good a fuel as glucose for exercise in normal subjects.

50 g fructose and 50 g glucose loads, naturally 13C labelled, were orally administered in random order to six healthy subjects submitted to 90 mn exercise at VO2 max/2 on a treadmill. 13CO2/12CO2 variations in the expired air were followed before and after exercise for a total of 240 min. On the whole, fructose appeared to be as good a fuel as glucose during exercise even if slight but significant differences in kinetics were observed: the delta 13C peak values at 90 min were significantly lower with fructose. Between 90 and 240 min, delta 13C remained higher but not significantly with 13C-fructose than with 13C-glucose. During exercise, plasma glucose and insulin levels were significantly lower (p less than 0.05 and p less than 0.01) after fructose than after glucose. We conclude that fructose can be readily used during exercise by healthy subjects.

Adult↗
PubMedDate not supplied

Bioartificial pancreas in autoimmune nonobese diabetic mice.

The authors wanted to test the long-term effectiveness of immunoisolation in the NOD mouse, an adequate model of Type I diabetes. Recipients were diabetic female NOD mice with sustained plasma glucose levels above 400 mg/100 ml. They were grafted intraperitoneally with permselective hollow fibers seeded with human insulinoma (n = 6), rodent insulinoma (n = 6), or human islets (n = 6). Controls were 15 nontreated diabetic females and 10 nondiabetic male NOD mice implanted with nonseeded macrocapsules. Electron microscopy (rectangular crystalline nucleoids characteristic of B-cells), in vitro release of insulin (during abrupt changes in glucose concentration from 40 to 400 mg/dl and return, M +/- SD insulin levels were 122 +/- 5 uu/ml and 315 +/- 17 at low and high glucose), evidence of binding hormone receptors (VIP and GIP, the binding sites being coupled with adenylyl cyclase stimulation) were used to assess the quality of the transplant. Survival was always prolonged in grafted animals. Taking complete and long-term (less than 3 months) correction of hyperglycemia as the criterion, the success rate was about 50% as observed in streptozotocin rats. Splenocytes isolated from cured and not cured recipients and injected into irradiated nondiabetic male NOD mice were always able to transfer the disease. Our bioartificial pancreas is efficient in preventing the recurrence of the disease in autoimmune diabetes.

Animals↗