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F W Kemmer

Publications and source records attributed to F W Kemmer.

32 records · Page 2Linked to original sources
PubMed1982

State of metabolic control determines role of epinephrine-glucagon interaction in glucoregulation in diabetes.

Epinephrine (0.1 micrograms.kg-1.min-1) was infused with or without somatostatin (0.1 microgram.kg-1.min-1) in six depancreatized dogs, studied under normo- and hypoinsulinemia to determine whether the participation of glucagon in epinephrine-induced hepatic glucose overproduction is governed by the degree of metabolic control. When normoglycemia was achieved by basal intraportal insulin replacement, insulin levels remained constant during the epinephrine infusion, and there was a twofold increase in extrapancreatic immunoreactive glucagon (eIRG) and glucose production (Ra). Although eIRG increments were prevented by somatostatin, the increase in Ra was undiminished, indicating that epinephrine can act independently of glucagon as in normal animals. During subbasal intraportal insulin infusion in the depancreatized dogs, insulin levels remained 35% lower than with basal replacement, and the animals were hyperglycemic. Epinephrine induced a similar twofold increase in eIRG as during normoglycemia, and again this rise was prevented by somatostatin. There was a significantly greater, threefold increase in Ra with epinephrine when the animals were hyperglycemic. This exaggerated response to epinephrine was not seen during eIRG suppression by somatostatin, suggesting that glucagon participated in the epinephrine-induced hepatic glucose overproduction when the depancreatized dogs were in poor metabolic control, as seen previously in alloxan-diabetic dogs. However, in the depancreatized, unlike in the alloxan-diabetic dogs, epinephrine-induced glucagon release was small. Thus, hypoinsulinemia appears to sensitize the liver to eIRG during epinephrine infusion. The fact that epinephrine induces hyperglycemia both in physiology and diabetes could indicate an important role in enhancing glucose transport in insulin-insensitive tissues.

Animals↗
PubMed1981

Importance of glucagon in mediating epinephrine-induced hyperglycemia in alloxan-diabetic dogs.

In normal dogs epinephrine stimulates glucose production (Ra) independently of glucagon. To investigate the role of this interaction in diabetes, epinephrine (0.1 micrograms . kg-1 . min-1) was infused for 90 min in five alloxan-diabetic dogs in the presence or absence of somatostatin (0.1 micrograms . kg-1 . min-1). In response to epinephrine, glycemia rose by 40% reflecting a near maximal (122%) increase in Ra. Plasma glucagon (IRG) rose to 953 pg/ml, whereas insulin (IRI) increased minimally. When somatostatin was infused with epinephrine to prevent the rise of IRG and IRI, there was only a marginal increase of glucose concentration (12%) and production (38%). The effect of somatostatin was reversed by infusing glucagon (10 ng . kg-1 . min-1) together with epinephrine and somatostatin into five additional alloxan-diabetic dogs. Increments in IRG, glycemia, and Ra were fully reestablished. A 100% FFA increase was observed in all three groups, indicating that the lipolytic effect of epinephrine was independent of glucagon. In conclusion, in diabetic dogs, in contrast to normal dogs, epinephrine induced a marked and prolonged increase in glucose concentration and production mostly through a stimulation of IRG secretion.

Alloxan↗
PubMed1981

Chromatographic pattern of extrapancreatic glucagon and glucagon-like immunoreactivity before and during stimulation by epinephrine and participation of glucagon in epinephrine-induced hepatic glucose overproduction.

To characterize the glucagon released in response to epineephrine in depancreatized dogs, plasma samples before and during epinephrine infusion were subjected to molecular-sieve chromatography on Bio-Gel P-30 columns. The chromatographic profile for extrapancreatic immunoreactive glucagon (eIRG) revealed two glucagon moieties of molecular weight 9,000 to 12,000. GLI of this molecular weight was released in response to epinephrine only under conditions of prevailing hyperglycemia. To determine if glucagon's participation in epinephrine-induced hepatic glucose overproduction in diabetes was dependent upon the degree of metabolic control, six conscious depancreatized dogs were infused with epinephrine or epinphrine plus somatostatin, under conditions of prevailing hyperglycemia or normoglycemia. Under normoglycemic conditions, epinephrine stimulated eIRG release, but there was a similar rise in hepatic glucose production (Ra) with or without glucagon suppression by somatostatin. Under hyperglycemic conditions, epinephrine stimulated eIRG and GLI release, and the rise in Ra was significantly greater with epinephrine than with epinephrine plus somatostatin infusion. Thus, under conditions of good metabolic control, epinephrine increased hepatic glucose production independently of glucagon, whereas with poor metabolic control, glucagon contributed to hepatic overproduction of glucose.

Animals↗
PubMed1980

Oxygen consumption in perfused skeletal muscle. Effect of perfusion with aged, fresh and aged-rejuvenated erythrocytes on oxygen consumption, tissue metabolites and inhibition of glucose utilization by acetoacetate.

1. O2 consumption, glucose metabolism and the energy status of skeletal muscle were compared in isolated rat hindquarters perfused with aged (21--35 days), fresh and aged-rejuvenated human erythrocytes. 2. The age of the erythrocytes did not affect O2 consumption, glucose utilization or lactate release either at rest or during exercise. The concentrations of ATP, phosphocreatine and lactate within the muscle were also unaffected by the use of aged erythrocytes. 3. Perfusion with acetoacetate did not inhibit glucose utilization; but, it caused a marked increase in the tissue concentration of citrate in the soleus, a slow-twitch red muscle, and a smaller increase in the gastrocnemius, which contains fast-twitch red and white fibres. Results were similar in hindquarters perfused with aged and aged-rejuvenated erythrocytes. 4. These findings suggest that perfusion with aged human erythrocytes does not cause major alterations in the metabolic performance of the isolated rat hindquarter.

Acetoacetates↗
PubMed1979

Glucose metabolism in perfused skeletal muscle. Demonstration of insulin resistance in the obese Zucker rat.

1. The effect of insulin (0.5, 10 and 50 munits/ml of perfusate) on glucose uptake and disposal in skeletal muscle was studied in the isolated perfused hindquarter of obese (fa/fa) and lean (Fa/Fa) Zucker rats and Osborne-Mendel rats. 2. A concentration of 0.5 munit of insulin/ml induced a significant increase in glucose uptake (approx. 2.5 mumol/min per 30 g of muscle) in lean Zucker rats and in Osborne-Mendel rats, and 10 munits of insulin/ml caused a further increase to approx. 6 mumol/min per 30 g of muscle; but 50 munits of insulin/ml had no additional stimulatory effect. In contrast, in obese Zucker rats only 10 and 50 munits of insulin/ml had a stimulatory effect on glucose uptake, the magnitude of which was decreased by 50-70% when compared with either lean control group. Since under no experimental condition tested was an accumulation of free glucose in muscle-cell water observed, the data suggest an impairment of insulin-stimulated glucose transport across the muscle-cell membrane in obese Zucker rats. 3. The intracellular disposal of glucose in skeletal muscle of obese Zucker rats was also insulin-insensitive: even at insulin concentrations that clearly stimulated glucose uptake, no effect of insulin on lactate oxidation (nor an inhibitory effect on alanine release) was observed; [14C]glucose incorporation into skeletal-muscle lipids was stimulated by 50 munits of insulin/ml, but the rate was still only 10% of that observed in lean Zucker rats. 4. The data indicate that the skeletal muscle of obese Zucker rats is insulin-resistant with respect to both glucose-transport mechanisms and intracellular pathways of glucose metabolism, such as lactate oxidation. The excessive degree of insulin-insensitivity in skeletal muscle of obese Zucker rats may represent a causal factor in the development of the glucose intolerance in this species.

Adipose Tissue↗
PubMed1979

Effect of physical training on glucose tolerance and on glucose metabolism of skeletal muscle in anaesthetized normal rats.

The effect of physical training on glucose tolerance in vivo and skeletal muscle glucose metabolism in vitro was investigated in normal rats. Treadmill running for 10 days up to 240 min/day led to a decrease of basal and glucose-stimulated plasma insulin levels without major alterations of the IV glucose tolerance (1 g/kg body weight). Swim training of two weeks' duration, i.e. exercise up to 2 X 75 min/day, which did not induce significant changes in body composition, skeletal muscle glycogen levels or citrate synthase activity, resulted in a significant improvement of IV glucose tolerance and substantial reductions of basal and glucose-stimulated plasma insulin levels. Associated with this apparent improvement of insulin sensitivity in vivo, significant increases of the insulin-stimulated glucose uptake (+ 55%) and lactate oxidation + 78%) in vitro were found on perfusion of the isolated hindquarter of swim-trained animals. It is suggested that mild physical training can improve glucose tolerance and insulin sensitivity in normal rats, at least in part, due to an increase of insulin sensitivity of skeletal muscle glucose metabolism.

Anesthesia↗
PubMed1977

Effects of metformin on glucose metabolism of isolated perfused rat skeletal muscle.

It was investigated whether N,N-dimethylbiguanide hydrochloride (metformin) lowers blood glucose levels by stimulating glucose uptake of skeletal muscle using the isolated perfused rat hindquarter. Osborne-Mendel rats were subjected to a special feeding regimen (food intake only 2 h daily) and were treated orally by metformin (125 mg/kg body weight twice daily) or placebo, respectively. The hypoglycemic effect of metformin could be demonstrated. Thereafter, control rats were perfused in the absence, and metformin-treated rats in the presence of added metformin (0.67 microgram/ml perfusate). Neither the basal nor the insulin-stimulated glucose uptake of skeletal muscle was increased by metformin. Lactate and alanine release, O2 uptake as well as the tissue metabolite levels of glucose, lactate, pyruvate, ATP and creatine-P remained unaffected. On the other hand, metformin caused a significant decline of lactate oxidation as well as an elevated glycogen content of skeletal muscle. It is proposed that the inhibition of lactate oxidation may under certain conditions be instrumental in the development of lactic acidosis associated with biguanide therapy.

Adenosine Triphosphate↗
PubMedDate not supplied

Obesity and hypertension: cardiovascular response of weight reduction.

There is a close epidemiological association between obesity and blood pressure for all age groups, although not every obese individual becomes hypertensive. In populations without age-related increases in body weight, an elevation of blood pressure with age is not seen. Treatment of obesity by weight loss decreases blood pressure substantially; however, in a minority of patients blood pressure does not fall with weight loss. Blood pressure generally decreases before normal weight is achieved. Blood pressure after weight loss remains reduced as long as there is no marked regain of body weight. Salt intake reduction does not appear to explain why weight reduction lowers blood pressure. Reduced levels of plasma renin activity, serum aldosterone levels, catecholamine levels, and serum insulin levels may be involved in the blood pressure lowering associated with weight loss. Since the risk to the hypertensive patient is not only determined by the blood pressure, an overall treatment that aims at reduction of all risk factors is advocated. Some risk factors, e.g., glucose intolerance, may be normalized only when desirable weight is achieved. Thus, in any obese hypertensive patient with other risk factors, normalization of excess body weight appears to be the first the most important step of any rational therapeutic strategy.

Adolescent↗
PubMedDate not supplied

Absorption kinetics of semisynthetic human insulin and biosynthetic (recombinant DNA) human insulin.

Absorption kinetics of subcutaneously injected human insulin (recombinant DNA) and semisynthetic human regular insulin were investigated and compared to the respective porcine insulin preparations in normal volunteers. The absorption of all regular human insulin preparations tested was accelerated as compared to porcine insulins. The clinical relevance of these findings in regard to the treatment of diabetes mellitus appears to be doubtful. As for mixtures of porcine regular and intermediate-acting insulin preparations, the absorption of human regular insulin is not altered when mixed with intermediate-acting human insulin.

Absorption↗
PubMedDate not supplied

Subcutaneous use of regular human insulin (Novo): pharmacokinetics and continuous insulin infusion therapy.

The absorption kinetics of human insulin (Novo) were studied and compared with those of purified porcine insulin preparations in seven healthy men. The absorption of insulin after subcutaneous injection of human insulin (Actrapid, Novo) was significantly accelerated and its hypoglycemic effect significantly stronger when compared with porcine insulin (Actrapid). No differences in the absorption kinetics were observed using human insulin (Monotard, Novo) and porcine insulin (Monotard) preparations, respectively. A clinical trial was designed to determine whether the pharmacokinetic differences were relevant for the clinical use of regular human insulin. The efficacy of human and porcine insulin (Actrapid) was tested in a double-blind crossover protocol in 12 type I diabetic patients treated with continuous subcutaneous insulin infusion. Near-normoglycemia was achieved with both types of insulin. Diurnal blood glucose values and excursions, insulin requirements, the frequency of mild hypoglycemic episodes, and the carbohydrate content of the diet were essentially identical. Thus, the differences between the absorption of human insulin and porcine regular insulin from a subcutaneous depot as observed in the pharmacokinetic studies in normal man do not appear to be relevant in the clinical practice of the subcutaneous insulin replacement therapy in type I diabetes mellitus at near-normoglycemia.

Absorption↗