Some aspects of the NMR-spectra of aporphine and phenanthrene alkaloids

Summary The C-11 proton of an aprophine possessing a C-1,2 methylenedioxy group falls relatively upfield between 7.47 and 7.86. Additionally, the i.c.s. for the two protons of the methylenedioxy group is large (4–12 Hz). The presence of a methylenedioxy at C-3,4 in a phenanthrene alkaloid also results in an upfield shift ( 8.95–9.00) of the C-5 proton.This project was supported by NIH research grant No. HL-12971, awarded by the National Heart and Lung Institute, PHS/DHEW.     

Alpha-receptor subsensitivity of isolated atria from rats following repeated injections of phenylephrine or isoprenaline

Summary Daily injections of phenylephrine or isoprenaline for 4 or 7 days lowered the chronotropic sensitivity of -adrenoreceptors in isolated rat atria.This study was supported by grants from the National Science Council of Finland.     

Effect of X-537A on the phosphorylated protein in sarcoplasmic reticulum vesicles

Summary The effect of the antibiotic X-537A on the phosphorylated ATPase (EP) was investigated. The results show that X-537A depresses the level of EP which is dependent on the Ca²⁺ gradient, while the Ca²⁺-independent EP is not affected. Acknowledgments. This work was supported by grants from the Instituto de Alta Cultura of the Portuguese Ministry of Education (No. CB/2) and the Calouste Gulbenkian Foundation.     

Does an inhibitor of mitochondrial adenylate kinase also affect oxidative phosphorylation?

Summary Adenylate kinase activity of intact mitochondria is strongly inhibited by Ap₅A, i.e.p ¹,p ⁵-Di (adenosine-5-) pentaphosphate, whereas oxidative phosphorylation is not affected. Therefore, Ap₅A is a useful tool to distinguish between oxidative and non oxidative ATP generating reactions.Acknowledgment. The generous support of Prof. Dr.Walther Lamprecht is gratefully acknowledged. J. L. thanks the Stipendienfonds des Verbandes der Chemische Industrie for a scholarship.     

Organization of myosin molecules in the muscle thick filament

Summary Tryptic treatment of muscle thick filaments reveals the underlying backbones of aggregatedl-meromyosin as a coli of 3 secondary filaments (helical repeat 130 nm) each in turn a coli of a 3 finer ones.     

Struktur-Wirkungsbeziehungen beim menschlichen Calcitonin. III. Die biologische Aktivität verkürzter oder an den Kettenenden modifizierter,synthetischer analoger

Summary Assays of 8 synthetic analogues of human calcitonin in rats showed that their hypocalcaemic activity was drastically reduced by deletion of the C-terminal amide group, chain-shortening or opening of the disulphide ring, but unaffected or enhanced by modification of the N-terminal amino group.

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II. vgl.R. Maier, B. Kamber, B. Riniker andW. Rittel, Hormon. Metab. Res.7, 511 (1975).

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Die hier verwendete, abgekürzte Schreibweise für Peptide folgt den Empfehlungen der IUPAC-IUB Kommission für Biochemische Nomenklatur, J.B.C.247, 977 (1972). Weitere Abkürzungen: HCT, Human-Calcitonin; PCT, Schweinecalcitonin; Bmp, -Mercaptopropionsäure (Desaminocystein); NMet, Normethionin (S-Methylcystein); -OMe, Methylester.     

Influence of cyclic nucleotides on protein synthesis in vascular smooth muscle

Summary The incorporation of leucice-¹⁴C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10^–3 M) and decreased by cyclic AMP (10^–3 M). There was no effect of 5 AMP (10^–3 M). The phosphodiesterase inhibiting drugs theophylline (10^–3 M) and papaverine (5×10^–5 g/ml) both decreased the leucine-¹⁴C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).     

Ecdysone 20-hydroxylase from the midgut of the tobacco hornworm (Manduca sexta L.)

Summary An ecdysone 20-hydroxylase enzyme system that converts -ecdysone to 20-hydroxyecdysone was prepared from the midgut of the tobacco hornworm prepupa. This partially purified enzyme is NADPH dependent and is localized in the mitochondrial fraction of the midgut tissue.     

Effect of 723-1723-1723-1on ethanol withdrawal in mice

Summary ⁹ (10 mg/kg, i.p.) administered to mice immediately after withdrawal from a 3-day exposure to ethanol vapor was found to intensify withdrawal reactions. No effect was seen when ⁹ was administered chronically during the exposure to ethanol.     

Biosynthesis ofα- andβ-ecdysone by the CrayfishOrconectes limosus in vivo and by its Y-Organs in vitro

Summary - and -ecdysone were synthesized from labelled cholesterol by premolt crayfish in vivo and by their Y-organs in vitro.