PubMed Health⌕ Search

Biomedical subjects

G Dietze

Publications and source records attributed to G Dietze.

At least 55 records · Page 3Linked to original sources
PubMed1988

[Inhibition of muscle amino acid release by infusion of a triglyceride emulsion].

Amino acid balances of 12 healthy volunteers were investigated with the forearm technique under the influence of an intravenous infusion of a long-chain triglyceride emulsion (LCT). Arterial concentrations of the amino acids declined due to a decrease of basal muscular release of most of the amino acids. Decreased phenylalanine and tyrosine output suggest that muscular proteolysis might be inhibited. With constant insulin and substantially unchanged blood glucose concentrations, this is apparently due to the increased concentration of free fatty acids.

Amino Acids↗
PubMed1987

Low-dose glucose infusion in patients who have undergone surgery. Possible cause of a muscular energy deficit.

To evaluate the effect of the glucose-induced insulin release on peripheral substrate metabolism, we studied muscle metabolism in seven patients after elective surgery and in four healthy volunteers combining the forearm and the euglycemic glucose clamp technique (insulin infusion, 0.2 mU/kg per minute). Arterial and deep venous concentrations of substrates and hormones were determined in the basal period and during steady state of the infusion period. After 90 minutes of insulin infusion, the whole-body glucose infusion rate was significantly lower in patients who had elective surgery, although plasma insulin concentrations were comparable. In both groups this was related to a reduced supply of free fatty acids and ketones in muscle. In controls the resulting lack of substrates in muscle appeared to be compensated by an enhanced uptake of glucose, not seen in the patients who had elective surgery. Surprisingly, as indicated by the significantly reduced lactate production (-0.15 +/- 0.05 vs -0.62 +/- 0.32 mumol/100 g per minute basal), in this group the glucose taken up was oxidized aerobically to a greater extent. However, the total resulting energy gain was small. Thus, a peripheral energy deficit might arise favoring increased oxidation of amino acids. To avoid this undesired side effect, only those substrates should be administered that minimize pancreatic insulin release.

Abdomen↗
PubMed1987

Captopril enhances insulin responsiveness of forearm muscle tissue in non-insulin-dependent diabetes mellitus.

Bradykinin infusion has been shown to improve glucose metabolism in non-insulin-dependent diabetic subjects (NIDD). Therefore, we tested the following hypothesis: inhibition of Kininase II, the bradykinin (BK) degrading enzyme, by captopril may also improve glucose metabolism in NIDD. Immediate effects of captopril on total body and peripheral glucose disposal were examined in five normotensive, normal weight NIDD and compared with five NIDD control subjects, well matched for age, weight and degree of fasting hyperglycaemia. The euglycaemic insulin clamp technique was employed in combination with the forearm catheter technique. After 90 min of insulin infusion a single dose of 25 mg captopril was administered orally, whereas in the control group a placebo was given. Captopril lead to a significant rise in total body glucose disposal and forearm glucose uptake, while in the control group no change was observed. Simultaneously, captopril lead to reduction in muscular release of lactate and pyruvate. We conclude that these results demonstrate the stimulatory effect of captopril on insulin-induced glucose disposal of the whole body, which appears to be a result of increased glucose utilization by peripheral tissues. Because of the described insulin-like activity of bradykinin, the concomitant accumulation of local kinins by captopril-induced inhibition of kininase II may represent an attractive hypothesis to explain the generated data sufficiently.

Alanine↗
PubMed1987

Inhibition of muscular amino acid release by lipid infusion in man.

Amino acid balances of healthy postabsorptive volunteers were investigated with the forearm technique under the influence of an intravenous infusion of triglyceride emulsions (LCT; MCT/LCT) [corrected]. A decrease of the basal muscular release of most of the amino acids, respectively an increase of pre-existent uptake rates [corrected]. In parallel, arterial concentrations of these amino acids declined. With constant insulin levels and substantially unchanged blood glucose levels, this inhibition of muscular proteolysis and/or stimulation of proteosynthesis is most probably due to the increased level of free fatty acids.

Amino Acids↗
PubMed1987

[Detection of substrate metabolism in skeletal muscles in the human].

The technical procedure of puncture and catheterization of arteria brachialis and a deep forearm vein in man and practical mode of blood sampling are described. For measurement of local blood flow depending on specific study design, venous occlusion plethysmography, i.m. or i.a. injection of 133Xenon can be used. The theoretical and practical problems of these methods are discussed in detail.

Catheters, Indwelling↗
PubMed1986

[Effect of fructose and sorbitol on insulin-induced hypoglycemia].

Twelve metabolically normal subjects were given 0.325 g/kg fructose or glucose dissolved in water 30 minutes after intravenous infusion of insulin, 0.05 U/kg. Blood glucose concentration was then measured for up to 60 minutes or until the onset of hypoglycaemia (study I). In study II two bread units (BU) were given to six subjects in the form of dark bread, as well as 12 g of butter and water. In two other groups, of six subjects each, 1 BU was substituted either by fructose or sorbitol. Seven subjects who had been given insulin but only water to drink afterwards served as the control group. In study I, both glucose and fructose achieved a clear slowing in the blood-sugar drop compared with the control group. But with glucose there was initially a slight rerise and the final hypoglycaemic level was somewhat delayed. This minor difference between glucose and fructose was not demonstrable in study II with the addition of fat and carbohydrate substitution. Each carbohydrate combination similarly influenced the course of blood sugar concentration. The results indicate that diabetics should continue to be given glucose rather than fructose or sorbitol if hypoglycaemia occurs. On the other hand, both fructose and sorbitol, although acutely less effective in raising blood glucose concentration, do counteract as carbohydrates the development of insulin-induced hypoglycaemia.

Adult↗
PubMed1986

Effects of kallikrein (K), bradykinin (B) and insulin (I), on substrate metabolism in the isolated perfused rat heart.

In the isolated rat heart preparation, perfused at physiological glucose levels, effects of kallikrein (K), bradykinin (B) and insulin (I) on carbohydrate metabolism have been compared. A flow- and I-independent K-effect, obviously working via proteolytic kinin formation, was shown. While I elevated glucose-uptake into the heart preferably via accelerated transport across the membrane and increased rates of glycogen synthesis, B and K significantly activated PFK and reduced myocardial glucose uptake. The latter effect is probably due to an accelerated glycolytic flux leading to decreased G6P-levels and thereby stimulating glycogenolysis. Since aprotinin was able to abolish the K-effect, the latter may possibly be mediated via kinin release.

Animals↗
PubMed1986

Inhibition of muscular glucose uptake by lipid infusion in man.

During a high-dose intravenous infusion of a mixed MCT/LCT-lipid emulsion and a conventional LCT-emulsion respectively, muscle substrate metabolism was investigated using the human forearm technique. With both lipid emulsions, a decrease in fractional muscular glucose extraction was seen, leading to significantly reduced muscular glucose uptake rates. An inverse linear relation between arterial tree fatty acids supply and fractional glucose extraction was seen suggesting that a mechanism according to Randle's glucose fatty acid concept is operating in skeletal muscle in man.

Journal Article↗
PubMed1986

Inhibition of muscular triglyceride lipolysis by ketone bodies: a mechanism for energy-preservation in starvation.

Using the forearm technique, muscle substrate balances were measured in healthy volunteers under the influence of a low dose intraarterial infusion of beta-hydroxybutyrate. The ketone body led to a prompt cessation of muscular release of glycerol and free fatty acids, indicating inhibited muscular triglyceride lipolysis. This finding confirms the concept of substrate regulation of muscle triglyceride lipolysis in vivo.

3-Hydroxybutyric Acid↗
PubMed1986

Improvement of impaired postoperative insulin action by bradykinin.

The effect of bradykinin on insulin-stimulated glucose metabolism was studied in 5 operated patients using the euglycemic insulin clamp technique and the forearm catheter technique. Insulin infusion [1.0 mU/(kg b.w. X min)] raised plasma insulin levels up to 73 muU/ml. Euglycemia was maintained by a computerized glucose infusion rate, amounting to 2.9 mg/(kg b.w. X min). Addition of bradykinin [1.5 micrograms/(kg b.w. X h)] resulted in a significant increase of the glucose infusion rate [+ 1.0 mg/(kg b.w. X min)] indicating elevated whole body glucose uptake. This was related to an enhanced forearm glucose uptake [+ 1.16 mumol/(100 g X min)]. Forearm blood flow remained stable.

Adult↗
PubMed1986

Angiotensin converting enzyme inhibitors in diabetes: experimental and human experience.

Peripheral glucose metabolism was studied during the influence of elevated systemic kinin levels by either application of exogenous bradykinin (BK) or inhibition of endogenous kinin degradation by angiotensin converting enzyme inhibitors (ACEI). In infusion experiments in streptozotocin-diabetic rats, both BK (0.3 micrograms/min) and ACEI (300 micrograms captopril/100 g) showed a significant reduction of elevated blood glucose levels. In man, non-insulin dependent diabetics (NIDD) and healthy subjects in postoperative (POP) stress were examined. Peripheral insulin-sensitivity and muscular glucose balance were determined using the glucose clamp technique and the forearm technique. In NIDD as well as in POP subjects, impaired peripheral insulin responsiveness, as evaluated by whole body glucose consumption, was improved up to 50% by application of BK (80 micrograms/h i.v.) or ACEI (25 mg captopril p.o.), respectively. This was most probably due to accelerated muscular glucose uptake which was assessed in the same experiment and found to be increased 2- to 3-fold under these conditions. As a molecular basis for the observed effects on muscular glucose uptake, phosphofructokinase was found to be markedly stimulated by BK (8 X 10(-10)mol/l) in the isolated perfused rat heart, suggesting accelerated glycolytic flux. It may be concluded that ACEI increase muscular insulin responsiveness, thus being beneficial in insulin-resistant states as well as in hypertension. This metabolic effect is most probably due to elevated systemic kinin levels. Further investigations are required to evaluate the clinical relevance of these findings.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1986

[Comparative studies of the metabolism of MCT/LCT and LCT emulsions in diabetics].

In 7 moderately overweight non-insulin dependent diabetics with slightly elevated triglyceride levels, disappearance rates of MCT/LCT- und LCT-emulsions were compared. 5 metabolically healthy volunteers served as control. During a 3-hour lipid infusion, serum triglycerides reached a steady state with both emulsions in the healthy controls, whereas in diabetic patients, steady state triglyceride levels were seen only with MCT/LCT. After the end of the lipid infusion, the longest half life value concerning the decline of triglyceride levels was found with LCT in diabetics, while significantly shorter and quite similar half life values were found with LCT in healthy controls and MCT/LCT in diabetics. The shortest half life for serum triglycerides was expectedly found in healthy controls. According to these data, parenteral nutrition with lipids in states of disturbed glucose and lipid metabolism--if necessary--should preferentially be done with MCT/LCT emulsions.

Diabetes Mellitus, Type 2↗
PubMed1985

Evidence for a substrate regulation of triglyceride lipolysis in human skeletal muscle.

Glycerol release from the human forearm which is generally used as a semiquantitative index of intramuscular lipolysis was studied under different hormonal influence and substrate supply in healthy volunteers and juvenile diabetics using the forearm technique. Acute insulin deficiency in juvenile diabetics failed stimulating the rate of muscular lipolysis since the rates of glycerol release in normals and diabetics were the same. In addition, in normal volunteers high physiological levels of insulin caused by an intraarterial infusion of the hormone exhibited no effect on the glycerol release from deep forearm tissue. Similarly, an intraarterial infusion of metaproterenol did not accelerate muscular glycerol release in normal man. However, in juvenile diabetics in acute insulin deficiency the same dose of the catecholamine increased the rate of muscular glycerol production. Elevated substrate supply during intravenous infusion of glucose or fructose yielded increased uptake of glucose and fructose into the deep forearm tissue and thereby promptly blocked muscular glycerol release in normal volunteers and in juvenile diabetics. These findings suggest that the rate of lipolysis in muscle tissue is not primarily under the control of hormones but rather by substrate supply.

Adult↗
PubMed1984

Substrate balances across skeletal muscle tissue in severe sepsis.

Substrate metabolism of skeletal muscle was studied by the forearm technique in eight patients with severe sepsis. The data were compared to those of 13 patients after elective surgery. In the septic group forearm blood flow was increased, but muscular utilisation of oxygen was diminished. Arterial concentrations of free fatty acids and ketone bodies were low. Thus, both only played a minor role in the supply of skeletal muscle with substrates. From the decreased production of lactate and alanine and the comparable utilisation of glucose we conclude that in the septic patients energy expenditure of skeletal muscle was mainly met by oxidation of glucose. In contrast to reduced lipolysis of adipose tissue intramuscular lipolysis may still be working since muscular production of lactate and glycerol was correlated. These findings suggest a changing pattern of arterial supply of substrates and utilisation of substrates by skeletal muscle during deterioration of clinical condition in the course of sepsis.

Journal Article↗
PubMed1984

[Postoperative insulin resistance of lipolysis and ketogenesis using the glucose clamp technic].

In seven healthy patients we studied the influence of various doses of insulin on the substrate concentration of free fatty acids and ketone bodies on the first day after major abdominal surgery by the glucose clamp technique. Insulin was infused at a rate of 0.2 and 1.0 mU/kg bw.min for ninety minutes and thus insulin concentrations were raised twice and seven times above the basal value. Already the minimal infusion of 0.2 mU insulin/kg.bw.min lead to a significant decrease of free fatty acids and ketone bodies. Our results show that even in postoperative stress the lipolysis of adipose tissue can be reduced by minimal insulin doses.

Abdomen↗