Über die Brenzkatechinamine im Froschherzen und in der Froschhaut vor und nach Verabfolgung von α-Methyldopa

Summary (1) The adrenalin of the frog heart was found to be localized mainly in the granular fraction (100,000g). After pretreatment with -methyldopa (-MD), the heart also contained -methyldopamine, -methylnoradrenalin, and -methyladrenalin. (2) -MD caused a maximal expansion of the melanophores. This action was counteracted byl-dopa, which per se caused a contraction of the melanophores. After pretreatment with -MD the skin contained besides adrenalin also -methyldopamine and -methyladrenalin. In addition also 5-hydroxytryptophan expanded the melanophores.     

Age-related differences in the urinary excretion of prostaglandin F2α catabolites in the rat

Summary Tritium-labelled PGF₂ was administered i.v. into rats of varying ages (2, 4, 6 weeks and adult). Urine was collected and assayed for radioactive products by thin-layer-chromatography. Results showed a distinctly different urinary profile between the 2-week-old and the adult rat. While the urinary pattern from the 2-week-old rat gave a single less polar product than PGF₂, the pattern from the adult rat gave products more polar than PGF₂. Urine from the 4- and 6-week-old rats gave a mixture of these types of products. These results indicate that some prostaglandin catabolic pathway (likely the -oxidative system) is activated in vivo within the 4–6-week postnatal period in the rat.Supported by a grant (MT-4181) to C.P.-A. from the Medical Research Council of Canada.This study is in partial fulfillment of the requirements for a Ph.D. degree in the Department of Pharmacology, University of Toronto.     

Alpha-amylase inhibitor increases plasma 3-hydroxybutyric acid in food-restricted rats

The effect on energy metabolism of delayed absorption of starch by inhibition of -amylase was examined by considering levels of plasma glucose and 3-hydroxybutyric acid (3-OHBA) in rats. Addition of -amylase inhibitor (AI) to a high starch diet delayed the plasma glucose response after feeding: peak plasma glucose levels in the control group occurred 15 min after feeding, whereas in the AI group this peak did not occur until 30 min after. The total plasma glucose response was not different between the two groups. Plasma 3-OHBA levels 1 day after food restriction increased approximately five-fold in both groups. After 3 days of food restriction, the AI group maintained the same level of plasma 3-OHBA as after 1 day of food restriction, while the control group showed significantly decreased levels of 3-OHBA. After 3 days of food restriction, plasma insulin levels were significantly decreased in the AI group compared with the corresponding levels of the control group and with levels before the restriction. There was no significant difference in body weight between the two groups. These findings suggest that delayed hyperglycemia due to delayed absorption of starch following AI loading may attenuate insulin secretion, leading to altered metabolism of 3-OHBA during the delayed response to energy deficit.     

Inhibition of human pancreatic elastase II activity on human aortic elastin by human α2-macroglobulin

Summary Human 2-macroglobulin-human pancreatic elastase II binding were investigated using a homologous substrate, human aortic elastin, in order to test the enzymatic activity. We demonstrated that two moles of 2-M are required to inhibit one mole of HPE_II when the enzyme is added to a mixture of elastin and 2-M. In addition, when the elastase-2-M complex is prepared under some circumstances, it exhibits an elastinolytic activity.     

Genetic control over the duration of G1 phase

or fi y G₁ , .     

Incorporation of α-aminobutyric acid into ergostine byClaviceps purpurea

Summary Claviceps purpurea 275 F.I. fed with -aminobutyric acid produces ergostine with the corresponding -hydroxy--aminoacid undiluted by endogenous aminoacid. Almost all the -aminobutyric acid not incorporated into the ergostine remains unchanged in the medium. The significance of these results in the biosynthesis of ergot alkaloids is discussed.     

Inhibition of lung carcinoma cell growth by high density lipoprotein-associated α-tocopheryl-succinate

-Tocopheryl-succinate (TS) is a synthetic, anti-neoplastic derivative of -tocopherol. Here we studied the effects of free and high-density lipoprotein subclass 3 (HDL₃)-associated TS on the growth of human (A549) and mouse Lewis (LL2) lung carcinoma cells. Both free and HDL3-associated TS inhibited A549 growth in a time- and concentration-dependent manner. Treatment of A549 cells with TS-enriched HDL3 led to DNA fragmentation and a time-dependent decrease in immunoreactivity of poly(ADP-ribose)polymerase. Uptake experiments revealed a high capacity for selective TS uptake in excess of holoparticle endocytosis. Overexpression of scavenger receptor class B, type I (SR-BI), the prime receptor mediating selective lipid uptake, in A549 cells resulted in significantly increased selective TS uptake, a finding associated with complete cellular growth arrest. The present in vitro findings were verified in an in vivo model: tumor inoculation in C57BL6 was performed with either wild-type, -galactosidase- or SR-BI-overexpressing LL2 cells. After tumor inoculation, the animals received six consecutive intravenous injections of TS. This experimental setup resulted in significantly reduced tumor burden in animals that were inoculated with SR-BI-overexpressing LL2 cells but not in animals inoculated with wild-type or -galactocidase-transfected cells. Based on our in vitro and in vivo findings, we propose that SR-BI could provide a novel route for HDL₃-mediated drug delivery of anti-neoplastic drugs.Received 8 March 2004; received after revision 7 April 2004; accepted 26 April 2004     

RNA synthesis in α-amanitin-poisoned rats: Prevention of recovery by inhibition of protein synthesis

Summary The treatment with cycloheximide of rats previously poisoned with -amanitin hinders the recovery of RNA synthesis observed in the liver of rats treated with -amanitin alone. The recovery of RNA synthesis can be ascribed to the capability of poisoned rats to synthesize new RNA-polymerase II.Acknowledgments: We thank ProfessorT. Wieland for the generous gift of -amanitin. This work was supported by grants from C.N.R., Rome, and by Pallotti's legacy for Cancer Research.     

G-protein signaling: back to the future

Heterotrimeric G-proteins are intracellular partners of G-protein-coupled receptors (GPCRs). GPCRs act on inactive G·GDP/G heterotrimers to promote GDP release and GTP binding, resulting in liberation of G from G. G·GTP and G target effectors including adenylyl cyclases, phospholipases and ion channels. Signaling is terminated by intrinsic GTPase activity of G and heterotrimer reformation – a cycle accelerated by regulators of G-protein signaling (RGS proteins). Recent studies have identified several unconventional G-protein signaling pathways that diverge from this standard model. Whereas phospholipase C (PLC) is activated by G_q and G, novel PLC isoforms are regulated by both heterotrimeric and Ras-superfamily G-proteins. An Arabidopsis protein has been discovered containing both GPCR and RGS domains within the same protein. Most surprisingly, a receptor-independent G nucleotide cycle that regulates cell division has been delineated in both Caenorhabditis elegans and Drosophila melanogaster. Here, we revisit classical heterotrimeric G-protein signaling and explore these new, non-canonical G-protein signaling pathways.Received 21 October 2004; received after revision 20 November 2004; accepted 30 November 2004     

Lack of tolerance development to tumor necrosis factor α inside the central nervous system

Tumor necrosis factor (TNF) was repeatedly microinfused into the lateral ventricle of guinea pig brains at a dose of 200 ng, 4 times within 150 min, at intervals of 3 days. In comparison to guinea pigs infused with solvent according to the same time schedule, the animals responded to TNF with pronounced fevers. The quantity of the fever response was the same after each of the 4 microinfusions of TNF. Three days after the last infusion of TNF or solvent all animals received an intramuscular injection of bacterial lipopolysaccharide (LPS). The fever in response to LPS was the same in both groups. Thus, the reported development of tolerance to repeated systemic administration of TNF^1–3 does not develop inside the blood-brain barrier. Also, the febrile response to LPS is not influenced by repeated central pre-treatment with TNF, whereas repeated peripheral treatment does have an effect.     

Axillary 5α-androst-16-en-3-one in men and women: Relationships with olfactory acuity to odorous 16-androstenes

Summary Axillary 5-androst-16-en-3-one (5-androstenone) levels were found to be significantly higher in men than in women but do not vary between left and right axillae, are not related to age, handedness or degree of hirsutism (in women) nor to anosmia to this steroid. In men (but not in women), levels are related linearly to axillary cholesterol concentrations but not to squalene. Olfactory thresholds for 5-androstenone varied widely, the lowest recorded being 0.2 ppb, but there was no difference in thresholds between men and women. Women (70%) found the smell repellant but anosmia did not differ greatly between men and women (9–20%). Anosmia to the smell of 5-androst-16-en-3-ol was most marked in women (90%) rather than in men (45%). Axillary 5-androstenone values were generally consistent with the musky or strong smells of male axillary extracts, compared with the sweet smell of those from female subjects.Supported by the Herbert Dunhill Trust.     

Orally administered melatonin stimulates the 3α/β-hydroxysteroid oxidoreductase but not the 5α-reductase in the ventral prostate and seminal vesicles of pinealectomized rats

Summary Pinealectomized rats were treated orally with melatonin (MEL) for 14 days. Prostates and seminal vesicles were investigated for the activity of the 4-3-ketosteroid-5-oxidoreductase (5-R) and of the 3/-hydroxysteroid-oxidoreductase (3-HSO). The activity of the 3a-HSO was significantly stimulated (p<0.01, Friedman test) when compared to controls. The activity of the 5-R did not change significantly.This work was supported by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 34 (Endokrinologie).     

Exchange of tritium from randomly tritiated taurocholate by microbial bile salt oxidoreductases

Summary Tritium distribution on randomly labelled taurocholate (TC) was estimated at 28%, 4%, 1% and <0.5% on the hydrogens opposite the 3-, 7- and 12-OH groups and taurine moiety respectively. Anomalously,C. perfringens 3-hydroxysteroid dehydrogenase (3-HSDH) catalyzed tritium loss of 36% on formation of 7-, 12-dihydroxy-3-keto-5-cholanoate, implying additional losses of tritium at other sites by this enzyme.This work is supported by the National Cancer Institute.     

Metabolism in Porifera. IX. Studies on the biological conversion of cholesterol into 19-nor-cholestanol by the spongeAxinella polypoides

Summary The conversion of cholesterol into 19-nor-5-cholestan-3-ol by the spongeAxinella polypoides involves a partial loss (40%) of the 3-hydrogen atom; moreover administration to the sponge of [4-¹⁴C]cholesterol tritiated at C-4 and C-7 showed that the 4- and 7-hydrogen atoms are retained in this conversion. A competitive uptake experiment, [4-¹⁴C]cholesterol vs. [7-³H₂]5-cholestanol, showed that the sponge utilized exclusively cholesterol for the production of 19-nor-5-cholestan-3-ol.Part of this work has been presented at the Nato Conference on Marine Natural Products (Jersey, Great Britain, October, 1976).-This contribution is part of the Programma finalizzato Oceanografia e Fondi marini-sottoprogetto Risorse biologiche C.N.R. Italy.     

Identification of 3α, 17α, 21-trihydroxy-5α-pregnane (allotetrahydro-17α-hydroxy-cortexone) and 3α,21-dihydroxy-5α-pregnane (allo-tetrahydro-cortexone) in human urine

Résumé Le 3, 17, 21-trihydroxy 5-pregnane (allo-tétrahydro-17-hydroxy-cortexone) et le 3,21-dihydroxy 5-prégane (allo-tétrahydro-cortexone) ont été identifiés dans l'urine humaine. Ces composés avaient les mêmes migrations chromatographiques avant ou après acétylation ou oxydation que les respectifs stéroïdes de synthèse.     

Age- and sex-related differences in the content of prothymosinα in rat tissues

Differences in the tissue content of prothymosin during the early postnatal development of male and female rats are reported. Thymus and spleen have been found to contain significantly higher amounts of prothymosin in the newborn and prepubertal animals, as compared to adults, whereas liver has been found to contain low levels of prothymosin throughout development. These findings indicate a functional association of prothymosin with the proliferating lymphoid tissues of the young rat.     

Positive correlation of responsiveness to catecholamines of the rat liver glycogenolytic receptor with other α-receptor responses

Zusammenfassung Durch die vollständige Dosis-Wirkungskurve der Katecholamin-i.p.-induzierten Leber-Glykogenolyse an der Ratte konnte deren Einfluss auf die -Rezeptoren nachgewiesen werden. Da eine Wirkung auf die -Rezeptoren (Lipolyse) ausschied, konnte es sich nur um einen -Effekt handeln.     

The molecular structure of the benzilic acid rearrangement product of 3α, 17β-diacetoxy-11-hydroxy-12-oxo-5β-androst-9(11)-ene

Zusammenfassung Die Struktur desp-Brombenzoates des Benzilsäureumlagerungsproduktes von 3, 17-Diacetoxy-11-hydroxy-12-oxo-5-9(11)-androsten wurde durch dreidimensionale Röntgenstrukturanalyse eines Einkristalls als 3-p-Brombenzoat des 11-Carboxy-3, 11, 17-trihydroxy-13-C-nor-5-androstan 11a, 17-Laktons erkannt.     

The tumor necrosis factor α of the bony fish seabream exhibits the in vivo proinflammatory and proliferative activities of its mammalian counterparts,yet it functions in a species-specific manner

Information on the bioactivities of non-mammalian cytokines is scant due to the lack of the recombinant molecules and specific antibodies. We produced the mature predicted peptide of tumor necrosis factor (TNF) from the bony fish gilthead seabream (Sparus aurata L.) (sbTNF), and its biological role was determined in vitro and in vivo. We first demonstrated by analytical size-exclusion chromatography that sbTNF is an oligomeric protein but the dimer appears to predominate over the trimeric form, in contrast to mammalian TNF. Intraperitoneal injection of native sbTNF resulted in (i) priming of the respiratory burst of the peritoneal exudate and head-kidney (HK) leukocytes, the latter being the bone marrow equivalent in fish; (ii) rapid recruitment of phagocytic granulocytes to the injection site, and (iii) induction of granulopoiesis in the HK. Interestingly, sbTNF was able to induce a strong proliferation of HK cells in vitro, whereas human TNF did not. Conversely, sbTNF was not cytotoxic for murine L929 fibroblasts.Received 12 February 2004; received after revision 15 March 2004; accepted 29 March 2004