Effect of vinblastine on pancreatic enzymes secretion induced by cyclic nucleotide derivatives

Summary Vinblastine did not affect the basal secretion of enzymes from the rat pancreas, but it potentiates the secretory response to dibutyryl cyclic AMP. This potentiation is confirmed by the observation of numerous pictures of exocytosis at the apical part of the acinar cell. Dibutyryl cyclic GMP by itself, or associated with vinblastine, failed to modify the spontaneous release of enzymes or the secretion induced by dibutyryl cyclic AMP.This work was supported by the Institut National de la Santé et de la Recherche Médicale (France).     

Effect of prostaglandin F2α on the secretion of pancreatic juice induced by secretin and by dopamine

Zusammenfassung Die Wirksamkeit von Prostaglandin F₂ (PGF₂) auf die exokrine Pankreassekretion wurde an einem mit Blut perfundiereten Pankreas-Präparat des Hundes untersucht. PGF₂ (100 g) hemmte die durch Sekretin stimuliete, aber nicht die durch Dopamin stimulierte Sekretion.     

Effect of prostaglandin E1 on rat gastric motility and cyclic nucleotide content.

Administration of exogenous prostaglandin E1 resulted in an increase in contractility of rat fundic muscle measured in vivo; a significant decrease in fundic tissue levels of cyclic- adenosine monophosphate and a significant increase in cyclic-guanosine monophosphate.     

Specific inhibition of a calcium dependent activation of brain cyclic AMP phosphodiesterase activity by vinblastine.

Vinblastine selectively inhibits the activation of brain cyclic AMP phosphodiesterase activity by Ca++-protein activator (50% inhibition by 2 x 10(-5) M). This inhibitory effect was reversed by excessive amounts of the activator, whereas large quantities of Ca++ caused only a slight suppression of the vinblastine effect. This result of vinblastine suggests a new site of its action and also suggests the possible role of protein activator, phosphodiesterase proteins or cyclic nucleotides in the previously known effects of vinblastine in vivo and in vitro.     

Effect of prostaglandin E1 on rat gastric motility and cyclic nucleotide content

Summary Administration of exogenous prostaglandin E₁ resulted in an increase in contractility of rat fundic muscle measured in vivo; a significant decrease in fundic tissue levels of cyclic-adenosine monophosphate and a significant increase in cyclic-guanosine monophosphate.     

Role of secretion in the dynamics of the maturation of predentin. Morphological, autoradiographic and freeze fracture study in the rat; changes induced by vinblastine

Morphological and autoradiographic data give evidence that secretion take place at the odontoblast process level according to a lateral axis, perpendicular to the maturation axis of the predentine. Induced modifications with vinblastine sulphate emphasize the importance of the pericellular space (150--200 nm) while the disorganization of the collagen fiber arrangement suggests the presence of flows. We propose an hypothesis which connects all these facts.     

Specific inhibition of a calcium dependent activation of brain cyclic AMP phosphodiesterase activity by vinblastine

Summary Vinblastine selectively inhibits the activation of brain cyclic AMP phosphodiesterase activity by Ca⁺⁺-protein activator (50% inhibition by 2×10^–5 M). This inhibitory effect was reversed by excessive amounts of the activator, whereas large quantities of Ca⁺⁺ caused only a slight suppression of the vinblastine effect. This result of vinblastine suggests a new site of its action and also suggests the possible role of protein activator, phosphodiesterase proteins or cyclic nucleotides in the previously known effects of vinblastine in vivo and in vitro.Our thanks to Drs A. R. Rhoads, C. B. Klee and R. A. Fergusson for analyzing PA preparations by gel electrophoresis and gel electrofocusing, and to Drs A. A. Suran and D. Soifer for their valuable critiques to this work. This work was partly supported by Biochemical Research Support Grant No. 5SO7RRO5361 to K.W. and Graduate Training Grant No. 5TO2GMO500002 to W.L.W. from NIH.     

Variations of cyclic nucleotide monophosphate levels during spontaneous uterine contractions.

Oscillations on the concentrations of cyclic nucliotides occurred during spontaneous rhythmic contractions in rat uterus. The levels of cyclic GMP and cyclic AMP were highest at the beginning of the contraction respectively the relaxation.     

Effect of acetone on VLDL secretion by the isolated rat liver.

High acetone levels occur in uncontrolled diabetes and after isopropanol administration to rats. In both conditions, very low density lipoproteins (VLDL) secretion is depressed. Acetone, hoever, failed to affect the VLDL secretion rate by the isolated perfused rat liver, suggesting that this metabolite is not involved in impaired VLDL production in diabetes and after isopropanol administration.     

Ionic effects on cyclic nucleotide accumulation in a phytophagous insect

Summary Incubation in solutions containing high potassium levels reduces specific accumulation of cyclic AMP in larval nerve cords ofManduca, sexta in vitro with or without serotonin or theophylline.Supported in part by NIH grant NS-09161-20 to R.W.N.     

Thiamine deficiency and protein secretion by pancreatic slices in vitro

Summary Pancreatic slices incubated in glucose medium take up oxygen and glucose and liberate pentose, pyruvate and proteins. Thiamine deficiency decreases oxygen consumption but increases liberation of pentose, pyruvate and proteins by pancreatic slices.     

The mechanism of external pancreatic secretion

Zusammenfassung Gegenwärtig vorliegenden Daten gemäss kann der Mechanismus der äusseren Sekretion der Bauchspiecheldrüsen am besten durch die Hypothese erklärt werden, dass zuerst eine bikarbonatreiche Lösung gebildet wird, die dann auf dem Weg durch die Gänge der Bauchspeicheldrüse mit dem extrazellulären Chlorid ausgetauscht wird. Die Wände der Gänge wirken als eine anionendurchlässige Membrane.     

Regulation of calcitonin release from the 6.23 rat C-cell line by cyclic nucleotide analogues and pharmacological mediators.

Calcitonin release from 6.23 rat medullary thyroid carcinoma C-cells was stimulated by dibutyryl cyclic AMP and inhibited by dibutyryl cyclic GMP in concentration dependent fashion. Histamine, isoproterenol, prostaglandin E2 and Bay K 8644 stimulated calcitonin release, while acetylcholine and serotonin had no significant effect on CT release.     

Effect of sodium butyrate in combination with prostaglandin E1 and inhibitors of cyclic nucleotide phosphodiesterase on human amelanotic melanoma cells in culture.

Sodium butyrate and cyclic AMP-stimulating agents (prostaglandin E1, papaverine, theophylline, and RO20-1724) caused reductions in the cell number (primarily due to reduction in cell division) when added individually to human melanoma cells in culture. However, the combination of sodium butyrate with one of the cyclic AMP-stimulating agents produced a marked reduction in cell number (primarily due to cell death).     

Preparation of hydrocarbon-adhering derivatives of water-soluble enzymes

Zusammenfassung Wasserlösliche Enzyme wurden mit saturierten alphatischen Kohlenwasserstoff-Diisozyanaten in Reaktion gebracht und die Bindung dieser Enzymderivate mit der Kohlenwasserstoffschicht stark gefördert. Bis zu 85% Katalysationstätigkeit der Schweinepankreas-Lipase konnte aus der Reaktionsmischung in Form einer beständigen Kohlenwasserstoff-Emulsion zurückgewonnen werden.     

Inhibitory effect of proteolytic enzymes on platelet aggregation induced by ADP or thrombin

Zusammenfassung Behandlung ungewaschener und gewaschener Thrombozyten mit proteolytischen Enzymen (Protease, Bromelain und Ficin) bewirkt eine Abnahme der Aggregationsfähigkeit von Thrombozyten mit ADP oder Thrombin.