Inhibition of rat liver adenyl cyclase by adenosine and adenine nucleotides

Riassunto L'attività adenilciclasica delle frazioni subcellulari di fegato di ratto fu inibita dall'adenosina, dall'AMP e dall'ADP (1 mM) del 60, 50 e 40%. Alla concentrazione di 0.08 mM, l'adenosina e l'AMP inibirono l'attività ciclasica del 40 e del 30%. L'IMP, l'inosina, l'adenina e l'ipoxantina furono senza effetto.

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This work was aided by Grants No. AM06034 and No. FR05641 from the National Institutes of Health, U.S. Public Health Service.     

The effect of exogenous conjugated bilirubin on the urinary excretion of unconjugated14C-bilirubin by the Gunn rat

Resumen La inyección de bilirrubina conjugada a ratas Gunn con ligadura coledociana, produce un aumento de la excreción urinaria de bilirrubina C¹⁴ exógena o de la endógena sintetizada a partir de la inyección de ALA-C¹⁴ en dichos animales. Dicho aumento fue probado por la cristalización de la bilirrubina radioactiva de muestras de orina y por la radioactividad presente en el azopigmento A separado por cromatografía sobre papel. El aumento de pigmento I, demostrado en el suero por partitión química y en la orina por columna cromatográfica de fase inversa, permiten suponer la formación de un complejo de bilirrubina no conjugada radioactiva y de bilirrubina conjugada, como mecanismo del pasaje mencionado.

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This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, República Argentina, National Institutes of Health, Bethesda, Md., USA and Ministerio de Salud Pública y Bienestar Social de la Provincia de Santa Fe, República Argentina.     

Isolation and electrophoretic identification of exogenous histone from rat blood plasma

Summary Histone fractions H1, (H2b+H2a) and H4 were isolated from rat blood plasma and electrophoretically identified 5 min after i.v. exogenous histone application.     

Regional distribution of adenine nucleotides,glycogen, glucose and lactate in the adult rat brain

Résumé Le cervelet contient des quantités plus grandes d'ATP, d'ADP et de nucléotides totaux que le lobe frontal du cerveau ou la moelle cervicale. Ces différences ne sont pas trouvées avec l'AMP. Le contenu en glycogène, en glucose et en lactate est plus grand dans la moelle cervicale que dans le cervelet et dans le lobe frontal.

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We wish to thank Dr.H. Rehkämper from Boehringer Mannheim GmbH, who kindly supplied us with all the enzymes, substrates and cofactors.     

The influence of estradiol on the distribution of exogenous cholesterol-4-C14 in the rat

Zusammenfassung Vorbehandlung mit Östradiolbenzoat führte bei kastrierten männlichen Ratten zu einer verminderten Aufnahme von oral zugeführtem Cholesterin-4-C¹⁴ in die Aorta. Bei kastrierten wie auch bei intakten Tieren war nach Östrogenbehandlung die Aufnahme von markiertem Cholesterin in die Leber erhöht. Durch Analyse der Faeces liess sich nachweisen, dass Östrogenbehandlung sowie Kastration die Sterolausscheidung beschleunigt.     

Isolation and electrophoretic identification of exogenous histone from rat blood plasma.

Histone fractions H1, (H2b+H2a) and H4 were isolated from rat blood plasma and electrophoretically identified 5 min after i.v. exogenous histone application.     

On the interaction of hypoxanthine with adenine

Résumé Une conversion non-enzymatique d'hypoxanthine en adénine fut proposée sur la base d'observations spectrophotométriques obtenues de solutions contenant adénine et hypoxanthine dans 1–5M de phosphate d'ammonium. Les résultats fournis par les expériences sur la radioactivité ne confirme pas la conclusion émise parBowne ² que hypoxanthine et adénine agissent l'une sur l'autre en solution concentrée de phosphate d'ammonium pour former de l'adénine.

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This work was supported by United States Public Health Service Grants No. AM-08897, No. AM-10126, and No. 2A-5124; a grant from The Arthritis Foundation (Northern California Chapter); and from the Committee on Research, University of California School of Medicine (San Francisco).     

Lack of immediate response of liver tyrosine-α-ketoglutarate transaminase to exogenous adrenaline in the adrenalectomized rat

Zusammenfassung Es wird eine Steigerung der Tyrosin--Ketoglutarat-Transaminase-Aktivität in der Rattenleber durch Adrenalin bestätigt und eine Verminderung der Transaminase-Aktivität nach Adrenalektomie durch Adrenalin nachgewiesen.     

Uptake of exogenous protein by supraependymal cells of the feline area postrema

Summary Supraependymal cells occurring on the surface of the feline area postrema were examined for phagocytic ability. It was shown that they could ingest exogenous horseradish peroxidase that was experimentally introduced into the brain ventricular system. The cells thus bear functional as well as ultrastructural attributes of macrophages, similar to those found in the third ventricle and subarachnoid space.We thank J. Stevens and A. Fenton for technical assistance. Supported by the Medical Research Council of Canada.     

Androgen dependency of hepatic hydroxysteroid dehydrogenases in the rat: Prepubertal responsiveness and unresponsiveness towards exogenous testosterone

Summary The prepubertal responsiveness of 3 typical androgen-dependent enzyme activities, namely 20-ketoreductase, 3- and ⁴-3-hydroxysteroid dehydrogenase, towards a large dose of testosterone was investigated. The androgen induced the activity of the 3-enzyme prepubertally in both sexes.This investigation was supported by the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 87, Endokrinologie).     

An assessment of the effect of hormone and neurotransmitters on adenine and gluanine derivatives simultaneously in rat brain cortical slices

Summary A 2-dimensional thin-layer method has been developed for the separation on cellulose of adenine and guanine derivatives. Using incubated rat cerebral cortex slices it was shown that noradrenaline and acetylcholine stirnulated cAMP and cGMP production respectively but glutamate and -aminobutyric acid stimulated production of both cyclic nucleotides.     

Uptake of exogenous protein by supraependymal cells of the feline area postrema.

Supraependymal cells occurring on the surface of the feline area postrema were examined for phagocytic ability. It was shown that they could ingest exogenous horseradish peroxidase that was experimentally introduced into the brain ventricular system. The cells thus bear functional as well as ultrastructural attributes of macrophages, similar to those found in the third ventricle and subarachnoid space.     

An assessment of the effect of hormone and neurotransmitters on adenine and guanine derivatives simultaneously in rat brain cortical slices.

A A 2-dimensional thin-layer method has been developed for the separation on cellulose of adenine and guanine derivatives. Using incubated rat cerebral cortex slices it was shown that noradrenaline and acetylcholine stimulated cAMP and cGMP production respectively but glutamate and gamma-aminobutyric acid stimulated production of both cyclic nucleotides.     

Differential effects of calcium channel blockers on the responses of the rat vas deferens to intramural nerve stimulation and exogenous drugs

The calcium channel blockers, nifedipine and verapamil, have separate effects on the phases of nerve-induced twitches which are not reflected by their actions on the responses to exogenous NA, ATP and the stable ATP analogue, alpha, beta-mATP. This implies that different calcium channels are used according to the manner of stimulation.     

Differential effects of calcium channel blockers on the responses of the rat vas deferens to intramural nerve stimulation and exogenous drugs

Summary The calcium channel blockers, nifedipine and verapamil, have separate effects on the phases of nerve-induced twitches which are not reflected by their actions on the responses to exogenous NA, ATP and the stable ATP analogue, ,-mATP. This implies that different calcium channels are used according to the manner of stimulation.