| 1. |
- Agardh, Carl-David, et al.
(författare)
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The influence of plasma insulin concentrations on tissue insulin levels in rodents: a study of the diabetic Chinese hamster and the ob/ob mouse
- 1986
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Ingår i: Metabolism, Clinical and Experimental. - : Elsevier BV. - 1532-8600. ; 35:3, s. 244-249
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Tidskriftsartikel (refereegranskat)abstract
- Immunoreactive insulin was measured in acid-ethanol extracts of kidney, brain, liver, and heart from genetically diabetic Chinese hamsters and their nondiabetic controls and from obese (ob/ob) mice and their thin littermates. Selected samples were filtered on Sephadex G-50 columns and the insulin concentration determined. There was a good correlation between the insulin level measured in the acid-ethanol extracts of tissues and the insulin level after gel filtration, suggesting that the concentration measured in the whole extract is representative of the true insulin content. The present data demonstrate that different extrapancreatic organs contain characteristic amounts of insulin that are often (sometimes several-fold) higher than the insulin level of plasma. The tissue insulin concentrations also exhibit a wide range of values, with occasional high values. The data also show a direct correlation between plasma and kidney insulins but no relationship between plasma and brain insulins and a mixed correlation among plasma and liver and heart insulins.
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| 2. |
- Dyrberg, Thomas, et al.
(författare)
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Humoral immunity in the spontaneously diabetic BB rat
- 1983
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Ingår i: Metabolism. - 0026-0495. ; 32:7 SUPPL. 1, s. 87-91
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Tidskriftsartikel (refereegranskat)abstract
- Litters of BB rats with an expected high and low incidence of insulin-dependent diabetes were followed from weaning until the age of about 140 days. Islet cell surface antibodies (ICSA) and lymphocyte antibodies (LA) were determined in a radioligand assay with fixed rat insulinoma (RIN 5F) cells, an insulin-secreting cell line, or spleen lymphocytes. In the low-incidence litter, 2 out of 14 rats had ICSA and LA; one showed insulitis at the end of the study. In the high-incidence litter, 3 out of 7 developed diabetes; all 3 showed ICSA at weaning. The remaining 4 showed insulitis. All 7 diabetes-susceptible rats had ICSA and LA at some time during the study. It is concluded that there is a high incidence of circulating ICSA and LA in the spontaneously diabetic BB rat. The antibodies can often be detected before the onset of diabetes, and may be implicated in the beta-cell destructive process and in the lymphocytopenia characteristic of the syndrome.
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| 3. |
- Stubbe, Ingo, et al.
(författare)
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Plasma lipoproteins and lipolytic enzyme activities during endurance training in sedentary men: changes in high-density lipoprotein subfractions and composition
- 1983
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Ingår i: Metabolism, Clinical and Experimental. - : Elsevier BV. - 1532-8600. ; 32:12, s. 1120-1128
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Tidskriftsartikel (refereegranskat)abstract
- Eighteen healthy sedentary males took part in supervised bicycle training for 50 minutes three to five times a week. Twelve subjects (group A) trained for 6 weeks at heavy intensity, and six subjects (group B) trained for 12 weeks at moderate intensity. Maximal oxygen uptake increased by about 20% (P less than 0.01). Body weight and composition as well as diet remained unchanged. After 6 weeks plasma high-density lipoprotein (HDL) cholesterol concentrations had increased by 7% (P less than 0.05) in all subjects. The increase was most marked in group B at 14% (P less than 0.05) compared to 3% in group A (ns). Apolipoprotein AI (apo AI) increased by about 7% in both groups (P less than 0.01). After 12 weeks HDL cholesterol and apo AI levels had almost returned to initial values. Measurements of HDL components showed increases of 6% to 12% in free cholesterol, cholesteryl ester (P less than 0.05), and phospholipid (P less than 0.01); whereas, the minor triglyceride fraction decreased by 20% (P less than 0.01). Zonal ultracentrifugation in four subjects revealed a preferential rise of about 35% in the HDL2 subfraction, increasing the HDL2/HDL3 ratio by about 20%. In parallel, the composition of the lipoprotein classes changed. The protein moiety of all classes, except low-density lipoprotein (LDL), expanded at the expense of the core components cholesteryl ester and triglyceride. Hepatic lipase (HL) activity decreased by 6% (P less than 0.05), and lipoprotein lipase (LPL) activity in adipose tissue increased by about 50% (P less than 0.05) during the first 6 weeks of training, while LPL activity in postheparin plasma and skeletal muscle did not change. The transient rise in HDL cholesterol levels was correlated (P less than 0.05) to the elevation of adipose tissue LPL activity. The alterations in HDL concentration were also related to changes in body composition and diet, especially to an increase in fat intake.
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| 4. |
- Tallroth, G, et al.
(författare)
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Regional cerebral blood flow in normal man during insulin-induced hypoglycemia and in the recovery period following glucose infusion
- 1992
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Ingår i: Metabolism, Clinical and Experimental. - : Elsevier BV. - 1532-8600. ; 41:7, s. 717-721
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Tidskriftsartikel (refereegranskat)abstract
- The effect of moderate hypoglycemia (p-glucose, 2.0 +/- 0.3 mmol/L; mean +/- SD) on regional cerebral blood flow (rCBF) was studied in a group of 10 healthy, right-handed men (aged 23 to 28 years) using an intravenous xenon 133 single photon emission computed tomography technique (SPECT). After 10 minutes of hypoglycemia, global CBF had increased to 46.3 +/- 9.6 mL/100 g/min compared with the initial normoglycemic flow of 38.6 +/- 6.8 mL/100 g/min (P less than .01). The relative distribution of the rCBF changed significantly (P less than .05, ANOVA) from before to during hypoglycemia. Of the 10 regions analyzed, the highest increments in rCBF during hypoglycemia were found in the frontal (21.5% +/- 15.2%) and parietal (20.6% +/- 14.2%) lobes, and the lowest (10.7% +/- 9.4%) were found in the pons/brainstem regions. The increase in rCBF persisted for 15 minutes after normalization of blood glucose. The persisting high flow after hypoglycemia affected all regions, but a further 10.1% +/- 7.2% increase was observed in the pons/brainstem area (P less than .05). The CBF was significantly higher in the right compared with the left hemisphere (2.8%, 1.2%, and 3.9%, respectively; P less than .05) in all measurements. A decrease in brain volume was found at the final examination, compared with the hypoglycemic state (2.6%; P less than .05). It is concluded that moderate hypoglycemia leads to a marked increase in CBF and in the relative distribution of rCBF, which persists in the immediate period after normalization of the blood glucose level.
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| 5. |
- Abrahamsson, Kate, 1959, et al.
(författare)
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Pivalic acid-induced carnitine deficiency and physical exercise in humans.
- 1996
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Ingår i: Metabolism: clinical and experimental. - : Elsevier BV. - 0026-0495. ; 45:12, s. 1501-7
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Tidskriftsartikel (refereegranskat)abstract
- To study the effect of carnitine depletion on physical working capacity, healthy subjects were administered pivaloyl-conjugated antibiotics for 54 days. The mean carnitine concentration in serum decreased from 35.0 to 3.5 mmicromol/L, and in muscle from 10 to 4.3 micromol/g noncollagen protein (NCP). Exercise tests were performed before and after 54 days' administration of the drug. At submaximal exercise, there was a slight increase in the concentration of 3-hydroxybutyrate in serum, presumably caused by decreased fatty acid oxidation in the liver. There was also a decreased consumption of muscle glycogen, indicating decreased glycolysis in the skeletal muscle. The muscle presumably had enough energy available, since there was no significant decrease in the concentration of adenosine triphosphate (ATP) and creatine phosphate during exercise. The work at maximal oxygen uptake (VO2max) and the maximal heart rate were reduced. Since VO2max is considered dependent on heart function, carnitine depletion seemed to affect cardiac function.
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| 6. |
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| 7. |
- Berts, Alf, et al.
(författare)
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Oscillatory Ca2+ signaling in somatostatin-producing cells from the human pancreas
- 1997
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Ingår i: Metabolism. - 0026-0495 .- 1532-8600. ; 46:4, s. 366-369
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Tidskriftsartikel (refereegranskat)abstract
- Oscillatory Ca2+ signaling was studied in human somatostatin-releasing pancreatic δ cells identified by immunostaining. A ratiometric fura-2 technique was used for measuring cytoplasmic concentrations of Ca2+ and Sr2+ in δ cells exposed to the respective cation. Rhythmic activity in terms of slow (frequency, 0.1 to 0.4 per minute) oscillations from close to the basal level was seen in the presence of 3 to 20 mmol/L glucose during superfusion with medium containing 2.6 to 5 mmol/L Ca2+ or 5 mmol/L Sr2. These oscillations could be transformed into a sustained increase by decreasing extracellular Ca2+ or adding 1 mmol/L tolbutamide or 20 nmol/L glucagon. Addition of glucagon to a medium containing 20 mmol/L glucose resulted in the generation of short (< 30 seconds) transients, which disappeared upon exposure to 100 nmol/L of the intracellular Ca2+-adenosine triphosphatase (ATPase) inhibitor thapsigargin. When analyzing small aggregates of islet cells, it became evident that oscillatory activity in δ cells can be synchronous with that in adjacent non—δ cells. It is concluded that secretion of pancreatic somatostatin in man involves Ca2+ signaling similar to that regulating the pulsatile release of insulin.
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