Effects of arsenite and oxamate on the in vitro functional activity of estrogen-dominated rat uterine horns

Summary Arsenite but not oxamate produce in vitro a distinct depression of estrogen-dominated uterine motility, both in the absence of substrate as well as in the presence of exogenous glucose or lactate. The addition of oxamate to preparations suspended in a medium with lactate as the sole external substrate ameliorates the depression of uterine motility elicited by arsenite.This work has been supported by grants 6638 and 6294 from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina.Senior Investigator of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.Junior Investigator of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Effect of hypophysectomy on the oxidative and glycolytic metabolism of hypothalamus

Resumen En el presente trabajo se ha estudiado el consumo de oxígeno y la producción de ácido láctico en hipotálamo anterior, medio y posterior en animales hipofisectomizados. Los resultados obtenidos indicaron que la hipofisectomía produce un significativo incremento en la actividad oxidativa del hipotálamo anterior y posterior sin modificar el hipotálamo medio.

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Supported by a grant of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.

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Research Fellow from Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.

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Established Investigator. Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina.     

Direct evidence favouring the notion that erythropoietin alters iron transport across the isolated intestinal tract of the rat

Summary A simple and reproducible method, using the isolated not everted intestine of the rat, for the study of iron transport is presented. Erythropoietin (ESF) enhanced significantly the passage of⁵⁹Fe across the intestine augmenting its movement at mucosal and serosal layers of the intestinal well.This work has been supported by grant 6638 from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.Senior Investigator of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Effect of hydrocortisone administration on erythropoiesis in the adrenalectomized dog

Resumen La administración de 2 mg/kg/día de hidrocortisona durante 40 días en perros adrenalectomizados 4 meses antes produjo elevación del volumen de la masa roja circulante y de la síntesis de hemoglobina. El tratamiento con la hormona en la dosis de 4 mg/kg/día durante los siguientes 40 días produjo más aumento de la actividad eritropoyética de la médula ósea, una gran proporción de la cuál fue inefectiva en términos de producción de eritrocitos, produciéndose un descenso de la masa roja circulante.

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Member of the Carrera del Investigador Científico del Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.

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This work was supported by Grant No. 1126d from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina.     

In vitro studies on bilirubin transport by the small intestine of the rat

Resumen Se estudió el transporte de bilirrubina no conjugada en asas intestinales aisladas y perfundidas de rata. Los resultados indican un pasaje bidireccional con la probable participación de un mecanismo de difusión simple.

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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 Publica y Bienestar Social de la Provincia de Santa Fé (Republica Argentina).     

Incorporation of phospholipids in Ehrlich ascites tumor cells

Summary Ehrlich ascites tumor cells (EATC) were incubated with unilamellar vesicles (UV) or multilamellar vesicles (MV). UV and MV were incorporated differently into EATC. The increase in³²P-phospholipid in EATC in the presence of UV was 12% in 300 min. Absorption of phospholipid from MV could account for only 3%. About 50% of the UV incorporation of³²P was by endocytosis and/or fusion.This work was supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina. J. L. Corchs is an investigator from the Consejo Nacional de Investigaciones Científicas y Técnicas.     

The effect of denervation on ATP dependent calcium uptake by microsomes of the submaxillary gland of rats

Zusammenfassung Nachweis, dass in einer Mikrosomen-Fraktion von Speicheldrüsen ein ATP-abhängiges Calciumtransportsystem existiert und dass dieses von der sympathischen Innervierung der Drüsen, nicht jedoch von der parasympathischen Innervierung abhängig ist.

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Members of the Carrera del Investigador Cientifico del Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.

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This work was supported in part by grants No. 3211/68 and 3155/67 from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina.     

The extracellular protease fromPseudomonas fluorescens

Summary An extracellular protease has been purified from cultures ofPseudomonas fluorescens. It is a metalloenzyme with a molecular weight of 37,000±3,700, able to digest casein, hemoglobin and gelatine.This work was supported by grants from the Consejo Nacional de Investig ciones Científicas y Técnicas de la República Argentina, and the Consejo de Investigaciones de la Universidad Nacional de Rosario. JJC is a member of the Carrera del Investigador Científico, and SMJ the recipient, of a schollarship, of the former institution.     

The mechanical and biochemical effects of pentoxifylline on the perfused rat heart

Summary Perfusion of the isolated rat heart at constant heart rate and coronary flow with the inhibitor of cyclic nucleotide phosphodiesterase, pentoxifylline (10^–4 moles/l), produced no significant effect on the maximum rate and the peak of contraction, but increased the maximum rate of relaxation. cAMP level and cAMP-dependent protein kinase activity were increased in the absence of changes in cGMP. The results were identical in hearts of reserpinized rats.This work was supported by grants from the Consejo Nacional de Investigaciones Cientificas y Técnicas and the Comisión de Investigaciones Científicas. Buenos Aires, Argentina.We thank Hoechst Laboratories for the partial support and Mrs Alicia R. Ramirez and María Prinzo for the excellent technical assistance.     

On the regulatory properties of a halophilic malic enzyme fromHalobacterium cutirubrum

Summary The NADP-linked malic enzyme fromHalobacterium cutirubrum is strongly inhibited by acetyl-CoA and NADH, and rather weakly inhibited by oxaloacetate and glyoxylate, in the presence of very high KCl concentrations (3,M), considered physiological for the extremely halophilic bacteria.This work was supported by grants from the consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina, and the Consejo de Investigaciones de la Universidad Nacional de Rosario. JJC and MCV are members of the Carrera del Investigador Científico of the former and the latter institutions, respectively.     

DNA synthesis in the pituitary gland of the rat: Effect of sulpiride and clomiphene

Summary Sulpiride administration to rats releases prolactin and increases DNA replication in the anterior pituitary gland. Clomiphene prevents the stimulation of DNA synthesis produced by sulpiride, but does not affect prolactin release from the gland. These findings suggest that the intracellular prolactin content of the anterior pituitary gland plays a role in the regulation of DNA synthesis through a mechanism mediated by oestrogens.This work was supported by PLAMIRH 99.178.1.78, by the Consejo Nacional de Investigaciones Científicas y Técnicas and by the Comisión Nacional de Energía Atómica (Argentina). We are grateful to Dr P. Scacchi for performing the radioimmunoassay and to Prof. C. J. Gómez for the opportunity to perform this work.     

Gamma globulins in the mice vaginal fluids: Cyclic and experimental variations

Summary The study of the gamma globulins in the vaginal fluids reveals that the lowest values were found in mice at estrus and in castrated mice 8 days after the estrogen treatment. We suggest that the variation of gamma globulins in the vaginal fluids is influenced both under physiological and experimental conditions by estrogens.This work was supported by a grant of the Conicet No. 4973 b/74.Fellow of Scientific Investigator Career. Consejo Nacional de Investigaciones Cientificas y Técnicas.Member of Scientific Investigator Career. Consejo Nacional de Investigaciones Científicas y Técnicas.     

The acidic glycosaminoglycans in gastric mucosa of athyroid rats: The effects of L-tri-iodothyronine

Summary Hyaluronic acid is increased about 12%, whereas dermatan sulfate is decreased about 34%, in gastric mucosa of athyroid rats when compared with controls. Administration of 2 doses of L-tri-iodothyronine reversed the effects of thyroidectomy.This work was partially supported by the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Effects of castration,estradiol and testosterone on tubulin levels of the medial basal hypothalamus and the adenohypophysis of the rat

Summary Tubulin levels of the medial basal hypothalamus (MBH) were greater in male than in female rats. Orchidectomy brought about a decrease of MBH tubulin concentration, whereas testosterone injection augmented it in the MBH and adenohypophysis. Estradiol administration augmented MBH tubulin and protein concentration.This study was supported in part by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina (CONICET) (grant No. 6638), and the Programa Latinoamericano de Investigación en Reproducción Humana (PLAMIRH 2.3.1.75 R).     

Oxidative metabolism of the hypothalamus in hypophysectomized-castrated rats

Resumen Los resultados obtenidos han indicado que el incremento del consumo de oxígeno en el hipotálamo anterior y posterior de los animales hipofisectomizados desaparece si estos animales son castrados simultaneamente con la hipofisectomía. Se discute la importancia de la presencia del testículo en la elevación de la actividad metabólica del hipotálamo luego de la hipofisectomía.

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Supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Cell proliferation in the rat pituitary gland: A mechanism of control in prolactin cells

Summary We investigated the relationship between prolactin content and DNA replication in the anterior pituitary gland. Thymidine incorporation in pregnant rats is significantly lower than in virgin controls. This is accompanied by a decreased activity of DNA polymerase. Sulpiride administration to pregnant rats enhances thymidine incorporation to levels similar to virgin controls. The results indicate a negative feedback between prolactin content and DNA synthesis in the rat anterior pituitary gland.We are grateful to Prof. Carlos J. Gómez for the opportunity to perform this work. These studies were supported by PLA-MIRH 99.178.1.78, by the Consejo Nacional de Investigaciones Científicas y Técnicas and by the Comisión Nacional de Energía Atómica (Argentina).     

Inhibition of the NADP-linked glutamate dehydrogenase fromTrypanosoma cruzi by silver nitrate

Summary The purified NADP-linked glutamate dehydrogenase fromTrypanosoma cruzi was strongly inhibited by silver nitrate. The inhibition was reversed by reduced glutathione, and was modified by the presence of the substrates during preincubation of the enzyme with the inhibitor.This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the Secretaría de Estado de Ciencia y Technología de la República Argentina. JJC is a member of the Carrera del Investigador Científico, and SMJ a Research Fellow, of the former Institution.     

The synovial fluid hyaluronic acid in rheumatoid arthritis

Summary The intrinsic viscosity of hyaluronic acid in synovial fluid decreases significatively in mild and severe arthritis (24% and 37% respectively). Variation in hyaluronic acid concentration parallels the above results. Chondroitin-6-sulfate can be detected in about 30% of the arthritic fluids.This work was partially supported by the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Cytogenetics of South American akodont rodents (Cricetidae). V. Segregation of chromosome No. 1 polymorphism inAkodon molinae

Summary Akodon molinae is polymorphic with 2n=42, 43, 44, where the metacentric autosome No. 1 is homologous to 2 acrocentrics 1a and 1b. Matings between 2n=43 heterozygotes 1/1a, 1b gave a surplus of 1/1 offspring, a moderate reduction of heterozygous and a strong reduction of homozygous 1a, 1b/1a, 1b offspring. The latter type also has a highly reduced fertility.This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, the Comisión de Investigaciones Científicas de la Provincia de Buenos Aires and the Organización de Estados Americanos.     

Effects of sexual hormones on gonadotrophin secretion in prepuberal female rats

Resumen Los estrógenos ejercen sobre la rate hembra un efecto de retroalimentación negativo sobre la secreción de gonadotrofinas a los 20 días de edad y un efecto positivo a los 28 días de edad. La testosterona inhibió la secreción de gonadotrofinas en ratas de 20 días, pero no tuvo efecto a los 28 días de edad. En los animales androgenizados al nacer ambas hormonas inhiben la secreción de gonadotrofinas a los 20 y a los 28 días de edad.

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Supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas. Repùblica Argentina.