Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 12 (1973), S. 8-15 
    ISSN: 1432-0827
    Keywords: Insulin ; Bone ; Calcium ; Resorption ; Orthophosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'administration d'insuline cristallisée à des rats thyroparathyroidectomisés provoque une augmentation de la calcémie et de la phosphorémie. Le calcium plasmatique s'élève de façon linéaire entre 31 et 250 m Unités d'insuline/100 g de poids corporel. La courbe obtenue n'est guère différente de celle obtenue par extrait parathyroidien. L'administration simultanée d'insuline et d'extrait parathyroidien à des rats thyro-parathyroidectomisés agit sur la calcémie et la phosphorémie par un effet additif. Lorsque des os frontaux d'embryons de poulet sont cultivésin vitro en présence d'insuline cristallisée, le taux de résorption augmente. L'insuline augmente le taux de consommation en glucose des explants et induit une accumulation de citrate dans le milieu de culture. L'insuline stimule donc la résorption osseuse.
    Abstract: Zusammenfassung Der Plasmagehalt an Calcium und Phosphor bei thyroparathyreoidektomierten Ratten wurde durch die Verabreichung von kristallinem Insulin erhöht. Das Plasmacalcium verhielt sich zwischen 31 und 250 m Einheiten Insulin pro 100 g Körpergewicht linear. Die Steigung der erhaltenen Kurve ist nicht signifikant verschieden von derjenigen, die nach Parathyreoidea-Extrakt erhalten wird. Die gleichzeitige Verabreichung von Insulin und Parathyreoidea-Extrakt von thyroparathyreoidektomierten Ratten hatte eine kumulative Wirkung auf den Gehalt von Calcium und Phosphor im Plasma. Wenn Stirnbeine von Kükenembryos mit kristallinem Insulinin vitro kultiviert wurden, erhöhte sich die Resorptionsrate. Das Insulin steigerte den Glucoseverbrauch der Explantate und verursachte eine Anreicherung von Citrat im Kulturmedium. Die Ergebnisse deuten auf eine Stimulation der Knochenresorption durch Insulin.
    Notes: Abstract the administration of crystalline insulin to thyroparathyroidectomized rats raised their calcium and phosphorus plasma levels. The plasma calcium gave a linear response between 31 and 250 mU of insulin/100 g body weight. The slope obtained is not significantly different from that obtained with parathyroid extract. The simultaneous administration of insulin and parathyroid extract to thyroparathyroidectomized rats affected the calcium and phosphorus plasma levels in an additive fashion. When chick embryo frontal bones were cultivatedin vitro with crystalline insulin the rate of resorption increased. Insulin increased the rate of glucose consumption by the explants and induced the accumulation of citrate in the culture medium. It is concluded that insulin stimulates bone resorption.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 16 (1974), S. 219-226 
    ISSN: 1432-0827
    Keywords: Bone ; Phosphate ; ATP ; Calcium ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract An active constituent of the leaves ofSolanum malacoxylon (SM) is shown to promote calcium resorption and citrate production in embryonic chick frontal bone culturedin vitro. When injected into rats, SM reduces the ATP content of liver and kidneys. This phenomenon may be related to the ability of SM to stimulate mitochondrial ATPase activity at pH 9.4. SM significantly reduces the concentration of phosphate necessary to alter the uptake of calcium and respiration of siolated mitochondria. The data suggest that SM influences calcium and phosphate metabolism by affecting ion movements into and out of mitochondria.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 14 (1974), S. 169-175 
    ISSN: 1432-0827
    Keywords: Galactose ; Glucose-6-phosphate ; Resorption ; Pyrophosphate ; Hydroxyproline ; Alkaline phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'effet du galactose sur le métabolisme osseux est étudié en soumettant de jeunes rats à un régime semi-synthétique contenant 35% de ce monosaccharide. Les animaux témoins reçoivent le même régime sans galactose, avec du glucose. L'effet d'une consommation de Ca−P, normal et faible, est étudié chez les témoins et les groupes soumis au galactose. La glucose-6-phosphate deshydrogénase osseuse est inhibée lorsque le galactose s'accumule dans les tissues. L'excrétion urinaire de calcium, pyrophosphate, aminopolysaccharides, hydroxyproline en phosphatase alcaline plasmatique (isoenzyme osseuse) est augmentée de façon significative par rapport aux témoins. Les animaux, recevant du galactose avec un régime faible en Ca et P, présentent une balance négative en Ca, due surtout à un excretion fécale plus élevée que les apports. Un rapport inverse est observé entre la balance calcique et l'ingestion alimentaire. L'effet nocif du galactose sur le métabolisme du calcium pourrait agir par l'intermédiaire d'une action sur les cellules osseuses et les fonctions rénales et intestinales, en rapport, peut-être, avec un trouble inconnu du métabolisme hydro-carboné.
    Abstract: Zusammenfassung Die Wirkung von Galaktose auf den Knochenstoffwechsel junger Ratten wurde untersucht, indem diese eine semisynthetische Nahrung erhielten, welche 35% dieses Monosaccharids enthielt. Kontrolltiere erhielten dieselbe Nahrung ohne Galaktose, aber mit Glukose. Die Kontrollgruppe und die Gruppe mit Galaktosenahrung erhielten eine niedrige und eine normal Ca−P-Einnahme. Die Glukose-6-Phosphat-Dehydrogenase des Knochens wurde gehemmt, wenn Galaktose im Gewebe zunahm. Die Urinausscheidung von Calcium, Pyrophosphat, Aminopolysacchariden, Hydroxyprolin und alkalischer Phosphatase des Plasmas (Knochen-Isoenzym) war signifikant höher als bei den Kontrollen. Die Tiere mit Galaktosezusatz und niedriger Ca−P-Aufnahme zeigten eine negative Calciumbilanz, die hauptsächlich durch eine fäkale Ausscheidung bedingt war, welche höher war als die Einnahme. Es wurde eine umgekehrt proportionale Beziehung zwischen Calciumbilanz und Nahrungseinnahme beobachtet. Die nachteilige Wirkung von Galaktose auf den Calciumstoffwechsel mag von einer Wirkung auf die Knochenzellen und auf die Nieren- und Darmfunktion herrühren, vielleicht im Zusammenhang mit einer noch unbestimmten Störung des Kohlenhydratstoffwechsels.
    Notes: Abstract The effect of galactose on bone metabolism was studied by feeding young rats a semisynthetic diet containing 35% of this monosaccharide. Control animals received the same diet without galactose but with glucose. Both a low, and a normal, Ca−P intake were studied in the control and galactose fed groups. Bone glucose-6-phosphate dehydrogenase was inhibited as galactose accumulated in the tissue. Urinary excretion of calcium, pyrophosphate, aminopolysaccharides, hydroxyproline and plasma alkaline phosphatase (bone isoenzyme) were significantly increased above control levels. Galactose fed animals on a low Ca and P diet showed a negative Ca balance, primarily due to a fecal excretion which was greater than intake. An inverse relationship between calcium balance and food intake was observed. The adverse effect of galactose on calcium metabolism may be mediated by an effect on bone cells and on renal and intestinal function, related perhaps to an as yet non-defined disturbance of carbohydrate metabolism.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0827
    Keywords: Respiratory alkalosis ; Ionized calcium ; 1,25 Dihydroxycholecalciferol ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The daily administration of supraphysiological doses of 1,25 dihydroxycholecalciferol (0.1–2.5 µg/d/100 g body weight) to rats, produced respiratory alkalosis. With the doses of 0.1–0.2 µg/d/100 g and feeding a diet with 0.7% of calcium, calcemias did not exceed 2.75 mM, and significantly reduced plasma ionized calcium levels were measured. The latter phenomenon was found associated with increased urinary excretion of cAMP, soft tissue calcium content, and polyuria with hypostenuria, all known effects of parathyroid hormone. These effects were absent in thyroparathyroidectomized rats treated in the same fashion. Present results suggest that the stimulus of low levels of plasma ionized calcium overcomes the probably inhibitory effect of the steroid on parathyroid hormone secretion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-2013
    Keywords: erythrocyte ; 1,25-dihydroxycholecalciferol ; 2,3-diphosphoglycerate phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The erythrocytes of rats treated with 1,25-dihydroxycholecalciferol or 1,25-dihydroxycholecalciferol glycoside showed decreased levels of 2,3-diphosphoglycerate. The same result has been obtained in vitro, indicating a direct effect of the sterol on the red cell. The glycoside is less active than the free sterol in vivo and more active in vitro. The decreased levels of diphosphoglycerate induced tissue hypoxia as shown by a higher plasma lactate/pyruvate ratio and a three fold increase in plasma erythropoietin concentration.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1432-5233
    Keywords: Key words Phosphaturia ; Glomerular filtration ; Tubular reabsorption ; Parathyroid hormone ; Thyroparathyroidectomy ; Fractional excretion of phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report deals with the relationships between glucose (G) and insulin on the tubular transport of phosphate (P) in chronically diabetic rats with high plasma levels of parathyroid hormone (PTH). Alloxan-induced diabetes leads to phosphorus depletion of the soft tissues. This phenomenon appears associated with weight loss and negative P balances caused by the increased urinary P excretion. Administration of 2 IU of insulin/100 g body weight (bw) to diabetic rats normalized their P balance and body weight. The effect of parathyroid function on the P metabolism of diabetic rats was investigated with balance experiments. Diabetic rats, intact or thyroparathyroidectomized (TPTX), have a greater urinary excretion of P than their controls. However, in control rats, the ratio intact:TPTX for urinary P is 1.0:0.76, showing the antiphosphaturic effect of parathyroid ablation. For diabetic animals, on the other hand, the ratio is 1.0:1.44. The simultaneous deficit of insulin and PTH thus quadruples the urinary P loss, instead of compensating for each other. The contribution of insulin deficit and hyperglycemia to the defect in tubular reabsorption (TRP) was investigated with clearance experiments (done on anesthetized, perfused rats). Five experimental groups were used: Controls (C), diabetics (D), controls+glucose (C+G), diabetics+insulin (D+I) and diabetics+insulin+glucose (D+I+G). All experimental groups showed a linear relationship between the TRP of P and G. The regression equation for C is significantly different (F=40.1, P〈0.001) from that of D animals. The slope value measure the number of µmoles of P per µmol of G reabsorbed. For C and D rats, the ratio P:G approximates 1:4 and 1:20, respectively. The increase in P:G ratios represents the competition between both substrates for tubular resorption. Glycemias up to 11 mM (C and D+I) exist concurrent with the P:G ratio 1:4. Glycemias above 25 mM (D, C+G and D+I+G) produce a P:G ratio of 1:20. Fractional excretion of P (FEP) increased significantly in untreated, chronically diabetic rats (0.47± 0.12 vs controls=0.05±0.01, P〈0.001). After a single intramuscular injection of insulin, the FEP decreased as a function of insulin levels. To normalize the FEP of diabetic rats in short-term experiments, insulin had to be administered in doses that produce plasma insulin levels 25 times greater than normal. The general information afforded by the present experiments shows that in untreated, chronically diabetic rats, insulin deficit plays an indirect role. The absence of PTH enhances the effect of hyperglycemia. The latter and the concurrent tubular overload of glucose are the cause of hyperphosphaturia in these animals.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...