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  • Insulin  (4)
  • isolated pancreatic islets  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 9 (1973), S. 135-139 
    ISSN: 1432-0428
    Keywords: Insulin secretion ; biosynthesis of proinsulin and insulin ; isolated pancreatic islets ; insulin content ; hypophysectomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Insulin secretion and biosynthesis of proinsulin and insulin were determined in isolated pancreatic islets of hypophysectomized rats. Control rats were of both same age and weight. Hypophysectomy was performed either 13 or 5 weeks prior to the investigation, the weight of the animals being either 80 or 170 g. Biosynthesis of insulin was estimated from the amounts of radioactivity incorporated into proinsulin and insulin after incubation of isolated islets at 50 or 300 mg% glucose in the presence of3H-leucine for 3 h. Islet proteins were separated on Sephadex G 50 fine. — Hypophysectomy resulted in a significant decrease of both glucose stimulated secretion and biosynthesis of insulin. It was found that this reduction was 1) more significant when compared with controls of same age 2) more marked in rats which had been hypophysectomized 13 weeks before than in rats after an interval of 5 weeks and 3) less in rats which had been hypophysectomized at a weight of 170 g than in rats in whom pituitary ablation was performed at a weight of 80 g. At basal glucose concentrations, no significant changes of both secretion and biosynthesis of insulin were apparent. The relation of radioactivity incorporated into proinsulin and insulin was unchanged under all conditions. Insulin content of the isolated islets used was found within about the same range in all rats, apart from the animals which had been hypophysectomized 13 weeks before. In islets of these rats, a reduction to 84% was observed. — Our findings may be explained by reduced sensitivity of the pancreatic B-cell to glucose and a slower rate of insulin biosynthesis after hypophysectomy.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 9 (1973), S. 140-144 
    ISSN: 1432-0428
    Keywords: Hypophysectomy ; growth hormone ; corticotrophin ; insulin secretion ; biosynthesis of proinsulin and insulin ; protein synthesis ; isolated pancreatic islets ; epiphyseal cartilage of the tibia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hypophysectomized rats were substituted with varying doses of human or porcine growth hormone (GH) as well as with ACTH for 6 or 12 days. Hypophysectomy was performed in animals of 80 or 170 g body weight either 12 or 4 weeks prior to the onset of the therapy. Increase in weight and the width of the epiphyseal cartilage were determined, insulin secretion and biosynthesis of proinsulin and insulin, were investigated in isolated pancreatic islets of the animals. — No differences were found between the effects of human and poreine GH preparations. Weight gain was similar in rats which had been hypophysectomized at a weight of 80 g either 12 or 4 weeks prior to the substitution. Secretion and biosynthesis of insulin which were both found to be reduced in isolated islets of untreated, hypophysectomized rats, were improved or normalized after substitution with GH (1 mg/kg/day) for 12 days. On the other hand, a therapy with GH for 6 days, even in tenfold daily dose (10 mg/kg), was ineffective in all rats which had been hypophysectomized at a weight of 80 g. Normalisation of lowered levels of blood sugar was the only positive effect observed after an administration of ACTH for 6 or 12 days. — It appears from our findings that, in contrast to the administration of ACTH, GH given to hypophysectomized rats for a longer period in relatively low doses may normalize both reduced secretion and biosynthesis of insulin.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Intestinal hormones ; isolated pancreatic islets ; insulin release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'effet des hormones intestinales sécrétine, pancréozymine, gastrine-pentapeptide et glucagon sur la sécrétion d'insuline des ilôts pancréatiques isolés du rat a été étudié. Seule la pancréozymine et le glucagon se sont avérés stimuler la sécrétion d'insuline des ilôts isolés. La pancréozymine a produit cet effet sans glucose et le glucagon ne l'a produit qu'en présence de glucose dans le milieu. L'effet de la pancréozymine a été montré à plusieurs reprises en utilisant les même ilôts dans un système de perifusion dynamique. Ces études impliquent une classification des hormones intestinales, qui stimulent la sécrétion d'insuline selon que le tissu pancréatique exocrine intact est présent ou non.
    Abstract: Zusammenfassung Der Effekt der intestinalen Hormone Secretin, Pankreozymin, Gastrin-Pentapeptid und Glucagon auf die Insulinsekretion isolierter Langerhans'scher Inseln der Ratte wurde untersucht. Nur Pankreozymin und Glucagon stimulierten die Insulinsekretion der isolierten Inseln, Pankreocymin ohne, Glucagon nur bei Zusatz von Glucose zum Medium. Dieser Effekt von Pankreozymin war wiederholt an denselben Inseln in einem dynamischen Perifusionssystem nachzuweisen. Die Untersuchungen zeigen, daß die insulinstimulierende Wirkung der intestinalen Hormone zum Teil an ein funktionsfähiges exocrines Pankreasgewebe gebunden ist, zum Teil davon unabhängig zustande kommt.
    Notes: Summary The effect of the intestinal hormones secretin, pancreozymin, gastrin-pentapeptide and of glucagon upon insulin secretion of rat isolated pancreatic islets were studied. Only pancreozymin and glucagon were found to stimulate insulin release from the isolated islets, pancreozymin without and glucagon only in presence of glucose in the medium. The effect of pancreozymin was repeatedly shown by using the same islets in a dynamic perifusion system. The studies imply classification of the insulin stimulating actions of the intestinal hormones according to dependence upon and independence of the presence of intact exocrine pancreatic tissue.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1440
    Keywords: Somatostatin ; Insulin ; C-peptide ; Diabetes ; Pituitary function ; Gastric acid secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of somatostatinoma syndrome in a 30-year-old woman is presented. Basal levels of growth hormone and of pancreatic and gastric hormones were reduced and the response of growth hormone, insulin and C-peptide to stimuli such as arginine, glucose, glibenclamide and calcium was virtually abolished. Similarly, gastric acid secretion, pancreatic exocrine function and intestinal absorption were significantly reduced. On the other hand, basal and stimulated levels of adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) were within the normal range. Plasma somatostatin-like immunoreactivity was increased to 600 2,000 pg/ml (normal: 88–140 pg/ml). Immunocytochemical studies demonstrated the presence of somatostatin immunoreactive material in the primary tumour in the head of the pancreas and in the liver metastases. In spite of two courses of chemotherapy with streptozotocin and 5-fluorouracil the patient died due to liver failure 5 months after the first admission to hospital.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1433-8580
    Keywords: Insulin ; Intestinal hormones ; Atropine ; Vagus ; Insulin ; Intestinale Hormone ; Atropin ; Vagus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung und Schluβfolgerung Bei 35 stoffwechselgesunden freiwilligen Probanden wurde vor sowie nach Atropingabe die Wirkung der intestinalen Hormone Sekretin und Cholecystokinin-Pankreozymin (CCK-PZ) auf die endokrine und exokrine Pankreasfunktion untersucht. Außerdem wurde die Wirkung von intravenös und oral bzw. intraduodenal verabreichter Glucose und Aminosäuren auf die Insulinsekretion, den Blutzucker und die freien Fettsäuren ebenfalls vor und nach Atropinmedikation geprüft. Intravenös verabreichtes Sekretin konnte weder in seiner exokrinen noch endokrinen Pankreasfunktion durch Atropin beeinflußt werden. Intravenös injiziertes CCK-PZ konnte mittels Atropin sowohl in seiner ekbolischen wie auch endokrinen Pankreasfunktion gehemmt werden. Die Wirkung von CCK-PZ ist somit an ein cholinerges System gebunden, so daß es erlaubt erscheint, bezüglich der Pankreozyminwirkung von einem synergistisch bzw. additiv wirksam werdenden „neurohormonalen“ Mechanismus zu sprechen. Die durch parenteral verabreichte Glucose oder Aminosäuren induzierte Insulinsekretion wurde durch Atropin nicht beeinflußt; hingegen hemmte Atropin dieβ-cytotrope Wirkung von oral bzw. intraduodenal verabreichter Glucose oder Aminosäuren. Dies läßt auf eine Abhängigkeit von einem cholinergen oder parasympathischen System in der Freisetzung dieser intestinalen Hormone schließen.
    Notes: Summary and Conclusions In 35 metabolically normal subjects the effect of i.v. secretin and cholecystokinin-pancreozymin (CCK/PZ) on the endocrine and exocrine pancreatic function was investigated, before and after atropine. In addition, the effect of oral, intravenous and intraduodenal administration of glucose and amino acids on blood sugar and free fatty acids before and after the injection of atropine was studied. The secretin stimulated endocrine and exocrine pancreas was not affected by atropine. However, atropine inhibited the ecbolic and endocrine pancreatic function after stimulation with CCK/PZ. Therefore, the effect of i.v. CCK/PZ seems to be mediated by the cholinergic system, or even a “neuro-hormonal” system which acts synergically or additively. No influence of atropine on the insulin secretion induced by i.v. glucose or amino acids was observed. On the other hand, atropine inhibited the beta-cytotropic effect of glucose and amino acids after oral or intraduodenal administration. These findings indicate that the release of these intestinal hormones is dependent on the cholinergic or parasympathetic system.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1433-8580
    Keywords: Oscillations ; Insulin ; Glucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study was designed to determine the effect of low dose continuous and oscillatory intraportal insulin infusions upon subsequent glucose-induced insulin release. In overnight-fasted and anesthetized rats with indwelling catheters in the jugular vein, carotic artery, and mesenteric vein insulin was infused intraportally for 3 h via the mesenteric vein catheter at a continuous rate of 45 µU/kg·min, or the same amount of insulin was administered at alternating high (72 µU/kg·min) and low infusion rates (18 µU/kg·min), respectively, in 2-, 4-, 8-, and 16-min cycles (oscillatory infusions). Another group received a continuous infusion of saline. Glucose (0.4 g/kg) was given i.v. 30 min after the end of the insulin or saline infusion. During the 3-h infusion of insulin or saline the peripheral glucose level remained unchanged in all groups. In response to the i.v. glucose load peripheral arterial plasma insulin levels were significantly elevated after preceding oscillatory infusions compared to the continuous insulin infusion. As compared to the group receiving saline the glucose-induced insulin response after continuous insulin infusion was significantly reduced. The plasma glucose responses were not different except for inexplicably elevated glucose levels in the 4-min cycle group. No difference was observed for plasma glucagon levels in all groups. The present data demonstrate an augmented responsiveness of theβ-cell to glucose after a preceding oscillatory infusion of insulin and an impaired responsiveness to glucose after continuous insulin infusion. This indicates that an oscillatory insulin release might be of importance for an adequate regulation ofβ-cell function.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1433-8580
    Keywords: H2-Receptor ; Somatostatin ; Pancreatic polypeptide ; Gastrin ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of histamine H2-receptor stimulation via the infusion of impromidine was assessed with regard to postprandial plasma insulin, pancreatic polypeptide (PP), somatostatin, and gastrin levels. The effect of impromidine was assessed in the postprandial state during a liver extract/sucrose test meal which had a buffer capacity to maintain the intragastric pH at a constant level for the time impromidine was infused. Postprandial plasma insulin and gastrin levels were not changed by impromidine (10µg/kg·h−1). Plasma somatostatin levels rose significantly, whereas the postprandial increase of plasma PP levels was attenuated. The effects on somatostatin and PP were antagonized by the infusion of cimetidine, a specific histamine H2-receptor blocker. In conclusion the present data demonstrate that in the postprandial state activation of H2-receptors stimulates somatostatin and inhibits PP release while insulin and gastrin release are not affected.
    Type of Medium: Electronic Resource
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