THE EFFECT OF NOREPINEPHRINE AND THEOPHYLLINE ON BLOOD GLUCOSE, PLASMA FFA, PLASMA GLYCEROL AND PLASMA INSULIN IN NORMAL SUBJECTS

Bradykinin can enhance skeletal muscle glucose uptake (GU), and exercise increases both bradykinin production and muscle insulin sensitivity, but bradykinin’s relationship with post-exercise insulin action is uncertain. Our primary aim was to determine if the B2 receptor of bradykinin (B2R) is essential for the post-exercise increase in GU by insulin-stimulated mouse soleus muscles. Wildtype (WT) and B2R knockout (B2RKO) mice were sedentary or performed 60 minutes of treadmill exercise. Isolated soleus muscles were incubated with [3H]-2-deoxyglucose ±insulin (60 or 100 μU/ml). GU tended to be greater for WT vs. B2RKO soleus with 60 μU/ml insulin (P=0.166) and was significantly greater for muscles with 100 μU/ml insulin (P<0.05). Both genotypes had significant exercise-induced reductions (P<0.05) in glycemia and insulinemia, and the decrements for glucose (~14 %) and insulin (~55 %) were similar between genotypes. GU tended to be greater for exercised vs. sedentary soleus with 60 μU/ml insulin (P=0.063) and was significantly greater for muscles with 100 μU/ml insulin (P<0.05). There were no significant interactions between genotype and exercise for blood glucose, plasma insulin or GU. These results indicate that the B2R is not essential for the exercise-induced decrements in blood glucose or plasma insulin or for the post-exercise increase in GU by insulin-stimulated mouse soleus muscle.

Download Full-text

Central and peripheral adrenoceptors affect glucose, free fatty acids, and insulin in exercising rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1988.255.4.r547 ◽

1988 ◽

Vol 255 (4) ◽

pp. R547-R556 ◽

Cited By ~ 4

Author(s):

A. J. Scheurink ◽

A. B. Steffens ◽

L. Benthem

Keyword(s):

Fatty Acids ◽

Blood Glucose ◽

Free Fatty Acids ◽

Blood Samples ◽

Beta Adrenoceptor ◽

Plasma Ffa ◽

Glucose Plasma ◽

Exercise Induced ◽

Counter Current ◽

Lateral Area

The effects of intravenously and intrahypothalamically administered alpha- and beta-adrenoceptor antagonists on exercise-induced alterations in blood glucose, plasma free fatty acids (FFA), and insulin were investigated in rats. Exercise consisted of strenuous swimming against a counter current for 15 min. Before, during, and after swimming, blood samples were withdrawn through a permanent heart catheter. Intravenous administration of the alpha-blocker phentolamine led to a reduction in glucose and a substantial increase in insulin levels. Infusion of phentolamine through permanent bilateral cannulas into either the ventromedial or lateral area of the hypothalamus (VMH and LHA, respectively) completely prevented the increase in glucose while the decline in insulin was unaffected. Infusion of phentolamine into the VMH caused much higher plasma FFA levels than in controls. The beta-blocker timolol given intravenously caused a delayed increase in glucose and prevented the increase in FFA. Infusion of timolol into either VMH or LHA caused a delay in the increase in both glucose and FFA. The results suggest that 1) both peripheral and hypothalamic adrenoceptors are involved in energy metabolism during exercise and 2) FFA, glucose, and insulin concentrations in blood are independently regulated by VMH and LHA.

Download Full-text

Fatty acid-independent inhibition of hepatic ketone body production by insulin in humans

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1988.254.6.e694 ◽

1988 ◽

Vol 254 (6) ◽

pp. E694-E699 ◽

Cited By ~ 2

Author(s):

U. Keller ◽

P. P. Gerber ◽

W. Stauffacher

Keyword(s):

Fatty Acid ◽

Plasma Insulin ◽

Ketone Body ◽

Plasma Free Fatty Acid ◽

Normal Subjects ◽

Heparin Infusion ◽

Group A ◽

Plasma Ffa ◽

Group B ◽

Body Production

To investigate whether elevated plasma insulin or glucagon concentrations are capable of modifying hepatic ketogenesis independently of plasma free fatty acid (FFA) concentrations, ketone body production was determined by [3–14C]acetoacetate infusions in overnight-fasted normal subjects during exogenous supply of FFA (Intralipid and heparin infusion). When plasma FFA concentrations were elevated from 0.73 +/- 0.07 to 1.53 +/- 0.16 mmol/l during low insulin concentrations (approximately equal to 13 microU/ml) in group A (n = 7), total ketone body production increased from 3.6 +/- 0.6 to 8.2 +/- 1.0 mumol.kg-1.min-1 (P less than 0.001). When plasma FFA were similarly elevated during raised plasma insulin concentrations (approximately equal to 110 microU/ml) in group B (n = 5), total ketone body production was only 3.8 +/- 0.8 mumol.kg-1.min-1 (P less than 0.01 vs. group A). Low plasma FFA and low insulin concentrations resulted in total ketone body production of 0.70 +/- 0.18 mumol.kg-1.min-1 in group C (n = 7; P less than 0.01 vs. groups A and B). Elevation of plasma glucagon during Intralipid infusion in group D (n = 7) failed to affect ketogenesis, but the beta-hydroxybutyrate-to-acetoacetate concentration ratio decreased significantly (P less than 0.01). The data indicate that elevation of plasma insulin to high physiological concentrations restrains FFA-induced ketogenesis.

Download Full-text

Reproducibility of energy intake, gastric emptying, blood glucose, plasma insulin and cholecystokinin responses in healthy young males

British Journal Of Nutrition ◽

10.1017/s0007114508042372 ◽

2008 ◽

Vol 101 (7) ◽

pp. 1094-1102 ◽

Cited By ~ 55

Author(s):

Nivasinee S. Nair ◽

Ixchel M. Brennan ◽

Tanya J. Little ◽

Diana Gentilcore ◽

Trygve Hausken ◽

...

Keyword(s):

Blood Glucose ◽

Gastric Emptying ◽

Energy Intake ◽

Plasma Insulin ◽

Intraclass Correlation ◽

Young Male ◽

Gastrointestinal Hormone ◽

Hormone Release ◽

Intraindividual Variation ◽

Glucose Plasma

Gastric emptying, as well as intragastric meal distribution, and gastrointestinal hormones, including cholecystokinin (CCK), play an important role in appetite regulation. The evaluation of gastrointestinal factors regulating food intake is commonly performed in healthy, lean, young male participants. It has, however, been suggested that there is a marked interindividual variability in the effects of nutrient ‘preloads’ on energy intake in this group. Whether there is significant intraindividual variation in acute energy intake after a nutrient preload, and, if so, how this relates to day-to-day differences in gastric emptying and gastrointestinal hormone release, is unclear. The purpose of the present paper is to evaluate the hypothesis that energy intake after a nutrient preload would be reproducible and associated with reproducible patterns of gastric emptying, intragastric distribution and gastrointestinal hormone release. Fifteen healthy men (age 25 (sem5) years) consumed a glucose preload (50 g glucose in 300 ml water; 815 kJ) on three occasions. Gastric emptying and intragastric meal distribution (using three-dimensional ultrasound), blood glucose, plasma insulin and CCK concentrations and appetite perceptions were evaluated over 90 min, and energy intake from a cold buffet-style meal was then quantified. Energy intake was highly reproducible within individuals between visits (intraclass correlation coefficient,ri = 0·9). Gastric emptying, intragastric meal distribution, blood glucose, plasma insulin and CCK concentrations and appetite perceptions did not differ between visits (ri>0·7 for all). In healthy males, energy intake is highly reproducible, at least in the short term, and is associated with reproducible patterns of gastric emptying, glycaemia, insulinaemia and CCK release.

Download Full-text