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  • 1
    ISSN: 1432-0428
    Keywords: Guinea pig ; extrapancreatic tissues ; insulin-related immunoactivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study we extracted guinea pig brain and testis with; the extract was adsorbed to and eluted from cartridges (the Sep-Pak C 18 procedure). We found this procedure superior for recovering crystalline insulin added to buffers or tissues, and for recovering endogenous insulin from plasma, but inferior for recovery of insulin from tissues. However, we did find ‘rat/pork’ type-insulin in guinea pig brain and testis (5–50 pg/g wet weight tissue). Our results with the Sep-Pak C18 procedures were reproduced by four other laboratories (who found 4–60 pg/g wet weight of tissue) and similar findings were also obtained by an independent investigator. Thus, we conclude that extrapancreatic tissues of guinea pigs have a second type of insulin-related material that is more typical of other mammalian insulins, but that the amount recovered is dependent upon the extraction procedure utilized.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Alloxan ; perfusion ; theophylline ; streptozotocin ; somatostatin ; insulin ; glucagon ; rat ; glucose ; pancreas ; arginine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The secretion of somatostatin and glucagon by the perfused rat pancreatico-duodenal preparation was examined in situ under control conditions and after the induction of acute insulin deficiency by alloxan or streptozotocin. A 10 min 0.625 mmol/l alloxan perfusion resulted in an immediate and transient increase in basal insulin and glucagon release and a slightly delayed and persistent increase in basal somatostatin secretion. The insulin responses to 16.7 mmol/l glucose, 1 mmol/l theophylline, and 19 mmol/l arginine alone or in combination were virtually eliminated by alloxan treatment, Somatostatin secretion in response to the stimuli was completely inhibited or markedly attenuated. The glucagon-suppressive effect of glucose was unaltered by alloxan and the stimulatory effect of arginine was enhanced. Addition of 1 μg/ml porcine insulin to the perfusion medium did not modify the alterations in somatostatin and glucagon responses to arginine. Streptozotocin treatment 90 min prior to the onset of perfusion resulted in changes in somatostatin, glucagon, and insulin responses to glucose and arginine similar to those of alloxan. The present results are consistent with an effect of alloxan and streptozotocin on the D cell similar to that on the B cell, namely, interference with a glucose-mediated effect on hormone secretion.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 8 (1972), S. 160-164 
    ISSN: 1432-0428
    Keywords: Hypothalamus ; obesity ; adipose tissue ; lipogenesis ; insulin ; hyperlipemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Du glucose U-14C a été injecté à des rats sevrés deux semaines après la destruction électrolytique des noyaux ventromédiaux de l'hypothalamus. Nous avons mesuré l'incorporation de la radioactivité dans les lipides du plasma de même que dans le foie, le tissu adipeux, le glycogène du diaphragme et du corps, les lipides totaux et les acides gras saponifiables. Au cours d'un régime avec ou sans graisse, les rats avec lésions incorporaient davantage de radioactivité dans tous les composés du tissu adipeux et dans les acides gras du foie, mais non dans le glycogène du foie. Pendant le régime avec graisse, la radioactivité des lipides du plasma était augmentée et celle des lipides totaux du foie restait constante, tandis que pendant le régime sans graisse, l'incorporation dans les lipides du plasma n'était pas augmentée, contrairement à l'incorporation dans les lipides du foie. La radioactivité des lipides totaux et des acides gras du diaphragme était augmentée tandis que celle du glycogène du diaphragme ne l'était pas. La radioactivité des lipides, des acides gras et du glycogène du corps était augmentée. - Le diaphragme a été également incubéin vitro avec le glucose U-14C ou le palmitate l-14C. L'incorporation du glucose dans les lipides totaux et les acides gras était augmentée tandis que son oxydation et son incorporation dans le glycogène ne l'étaient pas. L'oxydation et l'incorporation du palmitate dans les phospholipides étaient réduites, tandis que son incorporation dans les triglycérides était augmentée. - Les résultats ont été discutés dans le sens de changements similaires préalablement notés avec le tissu adipeuxin vitro.
    Abstract: Zusammenfassung Zwei Wochen nach elektrolytischer Zerstörung der ventromedialen Nuclei des Hypothalamus wurde entwöhnten Ratten U-14C-markierte Glucose eingespritzt. Es wurde die Inkorporation der Radioaktivität in Plasmalipide als auch in die Leber, das Fettgewebe, das Glykogen des Diaphragmas und des Körpers, die Gesamtlipide und die verseifbaren Fettsäuren gemessen. Bei fettfreier als auch bei fetthaltiger Diät inkorporierten Ratten mit Schäden im Hypothalamus mehr Radioaktivität in alle Fettgewebskomponenten und in Leberfettsäuren, aber nicht in Leberglykogen. Bei der fetthaltigen Diät war die Radioaktivität der Plasmalipide erhöht und die der gesamten Leberlipide unverändert geblieben. Bei einer fettfreien Ernährung war die Inkorporation in Plasmalipide nicht erhöht, während jene in Leberlipide angestiegen war. Die Radioaktivität der Gesamtlipide des Diaphragmas und der Fettsäuren war erhöht, diejenige des Diaphragmaglykogens jedoch nicht. Lipid-, Fettsäuren- und Glykogenradioaktivität des Körpers waren erhöht. - Das Diaphragma wurde ebenfallsin vitro mit U-14C-Glucose oder l-14C-Palmitat inkubiert. Die Glucoseinkorporation in Gesamtlipide und Fettsäuren war erhöht, dagegen nicht die Oxidation und Inkorporation in Glykogen. Die Palmitatoxidation und -inkorporation in Phospholipide war vermindert aber die Inkorporation in Triglyceride erhöht. — Die Ergebnisse werden im Lichte ähnlicher Veränderungen, die früher an Fettgewebenin vitro festgestellt wurden, diskutiert.
    Notes: Summary U-14C-Glucose was injected into weanling rats two weeks after electrolytic destruction of the ventromedial hypothalamic nuclei. Incorporation of radio-activity into plasma lipids as well as liver, adipose tissue, diaphragm and carcass glycogen, total lipid and saponifiable fatty acids was measured. On a fat free as well as on a chow diet, rats with lesions incorporated more radioativity into all adipose tissue components and into liver fatty acids but not into liver glycogen. On the fat containing diet (chow) radioactivity of plasma lipid was increased and that of liver total lipid unchanged, whereas on a fat-free diet incorporation into plasma lipid was not increased while that into liver lipid was. Diaphragm total lipid and fatty acid radioactivity was increased while that of diaphragm glycogen was not. Carcass lipid, fatty acid and glycogen radioactivity were increased. — Diaphragm was also incubatedin vitro with U-14C-Glucose or 1-14C-Palmitate. Glucose incorporation into total lipid and fatty acid was increased whereas oxidation and incorporation into glycogen were not. Palmitate oxidation and incorporation into phospholipid were decreased while incorporation into triglyceride was increased. - Results have been discussed in the light of similar changes previously noted with adipose tissuein vitro.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0428
    Keywords: Alloxan ; perfusion ; theophylline ; streptozotocin ; somatostatin ; insulin ; glucagon ; rat ; glucose ; pancreas ; arginine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The secretion of somatostatin and glucagon by the perfused rat pancreatico-duodenal preparation was examined in situ under control conditions and after the induction of acute insulin deficiency by alloxan or streptozotocin. A 10 min 0.625 mmol/l alloxan perfusion resulted in an immediate and transient increase in basal insulin and glucagon release and a slightly delayed and persistent increase in basal somatostatin secretion. The insulin responses to 16.7 mmol/l glucose, 1 mmol/l theophylline, and 19 mmol/l arginine alone or in combination were virtually eliminated by alloxan treatment, Somatostatin secretion in response to the stimuli was completely inhibited or markedly attenuated. The glucagon-suppressive effect of glucose was unaltered by alloxan and the stimulatory effect of arginine was enhanced. Addition of 1 μg/ml porcine insulin to the perfusion medium did not modify the alterations in somatostatin and glucagon responses to arginine. Streptozotocin treatment 90 min prior to the onset of perfusion resulted in changes in somatostatin, glucagon, and insulin responses to glucose and arginine similar to those of alloxan. The present results are consistent with an effect of alloxan and streptozotocin on the D cell similar to that on the B cell, namely, interference with a glucose-mediated effect on hormone secretion.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Within the past year, three similar peptides with specific growth hormone (GH) releasing effects have been extracted from human tissue, identified, and synthesized. Human pancreatic tumor GH releasing factor (1–40)-OH (hpGRF-40) was the sole hpGRF isolated from the pancreatic tumor of a patient in Charlottesville and was the predominant peptide isolated from the pancreatic tumor of a patient in Lyon. The Lyon tumor also contained hpGRF(1–37)-OH and hpGRF(1–44)-NH2. Both immunological and biochemical data suggest that hpGRF-40 and hpGRF-44 are present in the human hypothalamus and may be the human GH releasing hormone(s) (GHRH). In cultures of rat pituitary cells, hpGRF stimulates GH but affects neither basal and dopamine-inhibited prolactin release nor basal and gonadotropin releasing hormone (GnRH)-stimulated luteinizing hormone (LH) release. hpGRF stimulates cyclic AMP production within seconds, an effect which is blocked by somatostatin. In contrast, while hpGRF stimulates phosphatidylinositol turnover in the pituitary, the effect is not inhibited by somatostatin. In the human, hpGRF-40 (1 μg/kg) given intravenously (i.v.) stimulates GH release within 5 minutes. hpGRF-40 does not elevate serum prolactin levels, thyrotropin (TSH), LH, or corticotropin (measured indirectly through plasma cortisol), or blood glucose or plasma concentrations of insulin, glucagon, pancreatic polypeptide, cholecystokinin, gastrin, gastric inhibitory peptide, motilin, or somatostatin. When graded doses of hpGRF (0.1–10 μg/kg) are given i.v., no differences are noted in the maximal levels of serum GH achieved. Doses of 1, 3.3 and 10 μg/kg hpGRF-40 elicits a prolonged and biphasic pattern of GH release. Twenty-four hours after hpGRF-40 administration, serum somatomedin C is increased in 66% of subjects tested. Side effects including a feeling of warmth and facial flushing are observed in 66% (3.3 gmg/kg) and 100% (10 μg/kg) of men given hpGRF-40. hpGRF-40 (3.3 μg/kg, i.v.) selectively stimulates GH release and somatomedin C production in normal women, although no differences are found in GH responsivity during the menstrual cycle. hpGRF-40 given intranasally to normal men (30 μg/kg) stimulates GH release within 30 minutes. The calculated metabolic clearance rate for hpGRF-40 is 194±17.51/m2/d; the disappearance rate occurs as two phases: an initial equilibration phase (7.6±1.2 minutes) and a subsequent elimination phase (51.8±5.4 minutes). hpGRF-40 administered i.v. stimulates the release of GH in some adult patients with GH deficiency documented in childhood. Serum somatomedin C concentrations may increase in patients in whom hpGRF-40 fails to stimulate GH release. If patients with GH deficiency who do not respond to hpGRF-40 administration (10 μg/kg i. v.) are given the peptide (0.33 μg/kg i. v. every 3 hours) for five days, some will respond to a subsequent 10 μg/kg challenge. Of those who do respond initially, the response to the subsequent challenge may be greater. Serum somatomedin C increases significantly following the 5 days of intermittent administration of hpGRF-40. hpGRF-40 and/or hpGRF-44 may be the long sought GHRH. Clinical studies with hpGRF suggest that GH deficiency may often result from hypothalamic GHRH deficiency rather than pituitary disease. hpGRF and its analogues and antagonists may find therapeutic application in the treatment of GH deficiency and in other disorders in which an increase or decrease in the secretion of GH would be beneficial.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 31 (1969), S. 353-382 
    ISSN: 0066-4278
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Biology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 45 (1983), S. 95-107 
    ISSN: 0066-4278
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Biology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 12 (2000), S. 0 
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Glucocorticoids regulate growth hormone (GH) secretion by modulating both hypothalamic and pituitary function. At the level of the pituitary, glucocorticoids increase GH and GH-releasing hormone receptor (GHRH-R) gene expression. To test if glucocorticoids might also regulate the pituitary expression of the recently identified GH secretagogue (GHS) receptor, GHS-R; adult male rats were adrenalectomized or sham operated, and treated with the synthetic glucocorticoid (dexamethasone, 200 µg/day) or vehicle for 8 days. Pituitary GHS-R mRNA levels were assessed by reverse transcriptase polymerase chain reaction (RT-PCR). Adrenalectomy decreased pituitary GHS-R mRNA to 45% of vehicle-treated, sham-operated rats (P 〈 0.05). Administration of dexamethasone increased GHS-R mRNA levels in sham-operated as well as in adrenalectomized rats (199 ± 24% (P 〈 0.05) and 369 ± 48% (P 〈 0.01) of vehicle-treated controls). Addition of dexamethasone to primary rat pituitary cell cultures increased GHS-R mRNA levels in a dose- and time-dependent manner while the transcriptional inhibitor, actinomycin D, completely blocked the stimulatory action of dexamethasone. Taken together, these results suggest glucocorticoids directly increase pituitary GHS-R mRNA levels by stimulating GHS-R gene transcription.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Riassunto Il 2-desossi-d-glucosio somministrato nel ventricolo laterale del cervello del ratto provoca iperglicemia, inibizione della secrezione di insulina, iperfagia ed ipotermia a dosi che sono inefficaci per via sistemica.
    Type of Medium: Electronic Resource
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