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.     

Opposite effects ofβ-adrenoceptor stimulation and 8-bromo-cyclic AMP on potassium efflux in mammalian heart muscle

Summary -adrenoceptor stimulation by isoprenaline increases the potassium efflux in beating guinea-pig atria. This effect is not mimicked by 8-bromo-cyclic AMP, a cyclic AMP analogue which exerts a positive inotropic effect in this preparation.     

Furocaulerpin,a new acetylenic sesquiterpenoid from the green algaCaulerpa prolifera

Summary Furocaulerpin, an acetylenic sesquiterpenoid possessing a furan ring, has been isolated from the marine algaCaulerpa prolifera, and its stereostructure elucidated mainly on the basis of physico-chemical data.This work was carried out in the frame work of the Progetto Finalizzato per l'Oceanografia e i Fondi Marini, CNR, Rome. Thanks are due to the Centro di Metodologie Chimico-Fisiche of the University of Naples (Mr I. Giudicianni) for the determination of PMR-spectra.     

Failure of somatostatin to influence experimental tumor cell growth in vivo and in vitro

Summary The influence of somatostatin on tumor cell growth was studied in vivo in mice (sarcoma 180 ascites tumor and Lewis lung tumor) and in vitro on nontransformed and polyoma-transformed cell lines. 4 or 20 g/100 g of cyclic somatostatin and 4 g/100 g of linear protamin Zn-bound somatostatin were injected s.c. twice daily in the in vivo study. Cyclic somatostatin (1, 4 or 10 g/ml) was added twice daily to the cell cultures. Somatostatin administration influenced neither the survival of animals nor the growth rate of cultured cell lines. *** DIRECT SUPPORT *** A2025117 00011     

Concurrent occurrence of elevated ketone body and depressed carnitine level in underfed guinea-pigs

Summary Food ingestion of male guinea-pigs was restricted to 10 g/day. Total carnitine content of liver of the underfed animals fell to 3.75 moles per liver (46.1% of control). Serum level of total carnitine was 35.0 nmoles/ml (64.4%) in the underfed animals while they developed high ketonemia, 384.2 nmoles/ml (555.2%). In restricted animals the carnitine levels also decreased in the muscles.     

Some properties of the goat placental lactogen

Summary Goat placental lactogen was partially purified from a medium collected after placental tissue incubation. The data obtained by disc electrophoresis and isoelectric focusing experiments, as well as by means of radioreceptor assay methods, provide evidence of the similarity between the goat and ovine placental lactogen.The careful technical assistance of L. Tichovská is gratefuly acknowledged.     

Proteolytic activity on endogeneous substrates in cell-free extracts ofTrypanosoma cruzi

Summary Cell-free extracts ofTrypanosoma cruzi contain proteolytic activity able to degrade endogenous substrates. The activity was maximal at pH 3 to 4, had an optimal temperature of 65°C, and was strongly inhibited by N--p-tosyl-L-lysine chloromethyl ketone.This investigation received financial support from the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, the Fundación Julio Cherny, and the Ministerio de Salud Pública y Medio Ambiente de la República Argentina. The authors gratefully acknowledge the technical assistance of Mr Esteban Bontempi.     

The free radical oxidation of the tetrahydrocannabinols

Summary The free radical oxidation of ¹ and ⁶-tetrahydrocannabinol has been examined by spin trapping techniques and intermediates that would lead to cannabinol have been trapped. The 1st step in the oxidation of ¹-THC involves the removal of 3-H, while for ⁶-THC, either 2-H or 5-H. Intermediates were isolated which could be pyrolysed to the diene and cannabinol.     

Insulin stimulation of glucose and amino acid transport in mouse fibroblasts with elevated membrane microviscosity

Summary Basal and insulin-stimulated transport of 2-deoxy glucose and of -aminoisobutyric acid in mouse 3T3 fibroblasts were modulated by increasing the lipid microviscosity of the cell plasma membrane. The kinetics indicate that the insulin effect is induced either by recruitment of new transport carriers or by reduction of the translocation activation energy.This investigation was supported by grant No.5-R01-CA-27471-02, awarded by the National Cancer Institute, Department of Health, Education and Welfare.