[2-o-Iodotyrosine]-oxytocin and [2-o-methyltyrosine]-oxytocin: Basic pharmacology and comments on their potential use in binding studies

Summary Both [2-o-iodotyrosine]-oxytocin and [2-o-methyltyrosine]-oxytocin display only weak vasopressor and antidiuretic effects on rats. They inhibit the in vitro uterotonic action of oxytocin; this inhibition is not fully competitive. It is concluded that they are not suitable as markers for studies of uterine receptor for oxytocin.Supported by the Swiss National Science Foundation, grant No. 3.2080.73.Deceased 30 April 1975.     

2-o-Iodotyrosine]-oxytocin and [2-o-methyltyrosine]-oxytocin: basic pharmacology and comments on their potential use in binding studies

Both [2-o-iodotyrosine]-oxytocin and [2-o-methyltyrosine]-oxytocin display only weak vasopressor and antidiuretic effects on rats. They inhibit the in vitro uterotonic action of oxytocin; this inhibition is not fully competitive. It is concluded that they are not suitable as markers for studies of uterine receptor for oxytocin.     

Comparison of the effects of imidazo[1,2-a]pyridine-2-carbamates and benzimidazole-2-carbamates on the development of Hymenolepis nana in Tribolium confusum

The anthelmintic properties of several imidazo[1,2-a]pyridine carbamates and benzimidazole carbamates against Hymenolepis nana are compared. The results of this study, coupled with previous work, indicate that methyl 6-(trichloroethenyl)-imidazo[1,2-a]pyridine-2-carbamate has the potential of being a broad spectrum anthelmintic effective against both nematodes and cestodes.     

Decreased rates of Ca2+-dependent heat production in slow- and fast-twitch muscles from the dystrophic (mdx) mouse

Using a newly developed microcalorimetric approach to assess the rate of energy expenditure for intracellular [Ca²⁺] homeostasis in isolated muscles at rest, we found this was lower inmdx than in control mouse muscles, by 62% and 29% in soleus and extensor digitorum longus, respectively. Differences in total and Ca²⁺-dependent rates of specific heat production betweenmdx and control were enhanced during sustained, KCl-induced stimulation of energy dissipation. These results suggest that the low sacroplasmic energy status of dystrophic muscles is not due to any excessive energy expenditure for intracellular [Ca²⁺] homeostasis.     

Antagonism of prostaglandin-induced cyclic AMP accumulation in the rat anterior pituitary in vitro by somatostatin analogues.

The PGE2-induced cyclic AMP accumulation in the rat anterior pituitary in vitro is inhibited by [desamino1]-[desamino1] [descarboxy14]- and [D-Lys4]-somatostatin similarly to somatostatin, while the [descarboxy14]-somatostatin exhibits reduced activity; [D-Lys9]-somatostatin is ineffective at a higher concentration.     

Invertebrate neuropeptides resembling vasotocin and some analogues: synthesis and pharmacological properties

The solid phase synthesis of three invertebrate vasopressin-oxytocin homologs: AVP-like factor, F1(1), ([Leu2, Thr4] AVT)2 isolated from subesophageal and thoracic ganglia of Locusta migratoria3, Arg-conopressin-S4. ([Ile2, Arg4] AVT), Lys-conopressin-G4 ([Phe2, Arg4] LVT), both isolated from the venom of fish-hunting marine snails of the genus Conus and six of their analogues is reported. These analogues are: [Arg4] AVT, [Ile2] AVT, [Leu2] AVT, [Phe2, Arg4] AVT, [Arg4] LVT and [Ile2, Arg4] LVT. All peptides were tested for antidiuretic and vasopressor activities.     

Comparison of the effects of imidazo[1,2-a]pyridine-2-carbamates and benzimidazole-2-carbamates on the development ofHymenolepis nana inTribolium confusum

Summary The anthelmintic properties of several imidazo[1,2-a]pyridine carbamates and benzimidazole carbamates againstHymenolepis nana are compared. The results of this study, coupled with previous work, indicate that methyl 6-(trichloroethenyl)-imidazo[1,2-a]pyridine-2-carbamate has the potential of being a broad spectrum anthelmintic, effective against both nematodes and cestodes.Acknowledgments. We are indebted to Miss Marianne Hardy for excellent technical assistance. Our sincere thanks are extended to the Merck, Sharp & Dohme and Hoechst companies for the compounds tested in the present study.     

Extracellular Mg2+ regulates intracellular Mg2+ and its subcellular compartmentation in fission yeast, Schizosaccharomyces pombe

Effects of extracellular magnesium ions ([Mg²⁺]_o ) on intracellular free Mg²⁺ ([Mg²⁺]_i ) and its subcellular distribution in single fission yeast cells, Schizosaccharomyces pombe, were studied with digital-imaging microscopy and an Mg²⁺ fluorescent probe (mag-fura-2). Using 0.44 mM [Mg²⁺]_o , [Mg²⁺]_i in yeast cells was 0.91±0.08 mM. Elevation of [Mg²⁺]_o to 1.97 mM induced rapid (within 5 min) increments in [Mg²⁺]_i (2.18±0.11 mM). Lowering [Mg²⁺]_o to 0.06 mM, however, exerted no significant effects on [Mg²⁺]_i (0.93±0.14 mM), at least for periods of up to 30 min. Irrespective of the [Mg²⁺]_o used, the subcellular distribution of [Mg²⁺]_i remained hetero geneous, i.e. where the sub-plasma membrane region >cytoplasm >nucleus. [Mg²⁺] in all three subcellular compartments increased significantly, two- to threefold, concomitant with [Mg²⁺]_i when placed in 1.97 mM [Mg²⁺]_o . We conclude that [Mg²⁺]_i in fission yeast is maintained at a physiologic level when [Mg²⁺]_o is low, but intracellular free Mg²⁺ rapidly rises when [Mg²⁺]_o is elevated. Like most eukaryotic cells, yeast may have a Mg²⁺ transport system(s) which functions to maintain gradients of Mg²⁺ from the outside to inside the cell and among its subcellular compartments. Received 18 April 1996; received after revision 4 July 1996; accepted 26 July 1996     

On the synthesis of serine and homoserine samples asymmetrically labelled with tritium and deuterium in the hydroxymethylene group.

(1R) [1-3H, 2H1] 3-Phenylpropanol, the key intermediate in the synthesis of (4R) [4-3H, 2H1] D,L-homoserine and of the (4S)-isomer, is obtained from (1S) [1-2H1] 3-phenylpropanol and (1RS) [1-3H] ethanol upon incubation with yeast alcohol dehydrogenase and NAD+; under similar conditions 2-phenylethanol undergoes very small exchange with [1-2H2] ethanol.     

3[H]-Sulpiride labels mesolimbic non-dopaminergic sites that bind antidepressant drugs

3[H]-(-)-Sulpiride and 3[H]-spiperone binding was compared in rat amygdala, nucleus accumbens and striatum, using (+/-)-sulpiride to define specific binding. 3[H]-(-)-Sulpiride bound to twice as many sites in amygdala and nucleus accumbens as 3[H]-spiperone. 3[H]-(-)-Sulpiride binding was directed to these additional sites by using 1 microM spiperone to mask dopaminergic binding. The binding of 3[H]-(-)-sulpiride to these sites was high affinity, reversible, Na+-dependent, but not stereospecific. Metoclopramide, tiapride and antidepressant medications, but not other neuroleptics, ADTN, or serotonin displaced 3[H]-(-)-sulpiride binding to these sites. These data suggest that 3[H]-(-)-sulpiride labels mesolimbic sites other than dopamine receptors which may mediate antidepressant effects.     

Serotonin-stimulated protein phosphorylation in aortic smooth muscle cells

The effects of serotonin on the formation of inositol phosphates and protein phosphorylation were examined in cultured smooth muscle cells. Serotonin stimulated the formation of [3H]inositol monophosphate, [3H]inositol bisphosphate and [3H]inositol trisphosphate. This effect was prevented by 5-HT2 specific antagonist, 6-methyl-1-(1-methylethyl)ergoline-8-carboxylic acid, 2-hydroxy-1-methylpropyl ester [Z]-2-butenedioate (LY53857). Serotonin stimulated the phosphorylation of many polypeptides, among which a 20 kDa polypeptide was the most prominent. The phosphorylation was also inhibited by LY53857. LY53857 alone produced no effects on protein phosphorylation. The 20 kDa polypeptides were also phosphorylated by the addition of 12-O-tetradecanoylphorbol-13-acetate. These results suggest that serotonin stimulates protein phosphorylation through 5-HT2 receptors and possibly activates protein kinase C in intact vascular smooth muscle cells.     

Effects of [N-(2-oxo-3,5,7-cycloheptatrien-1-yl)] aminooxoacetic acid ethyl ester (AY-25,674) on cyclic 3',5'-nucleotide formation and phosphodiesterase activity.

The orally-effective antiallergic compound [N-(2-oxo-3,5,7-cycloheptatrien-1-yl)] aminooxoacetic acid ethyl ester (AY-25,674) exhibited a potency equivalent to or 3 times less than theophylline in inhibiting guinea-pig lung and beef heart PDE, respectively, AY-25,674 did not affect the basal activity of guinea-pig lung adenyl cyclase. Although part of the antiallergic activity of AY-25,674 may be due to the ability to elevate cyclic AMP levels by PDE inhibition, other modes of action appear to be of greater relevance.     

Reaction of resorcinol with isoprene

Zusammenfassung Die Synthese von 7-Hydroxy-2, 2-dimethylchroman, 6,7-Dihydro-2,2,8,8-tetramethyl-8H-[1]pyrano[3,2-g]chroman und 9,10-Dihydro-2,2,8,8-tetramethyl-8H-[1]pyrano[2,3-h]chroman aus Resorcin und Isopren oder 1-Bromo-3-methyl-2-buten wird beschrieben.     

Mechanism of age-dependent involution in embryonic chick notochords

To study the possible mechanism of the age-dependent involution of the notochord, isolated mesenchymefree notochords of chick embryos were cultured in vitro and compared with their counterparts in vivo. Two different aspects were evaluated: (1) DNA synthesis measured by [³H]thymidine incorporation and visualized by autoradiography and (2) cell death quantified by counting the number of pyknotic nuclei. The results demonstrate that [³H]thymidine uptake by notochords shows an age-dependent decrease in vitro as well as in vivo. The number of [³H]thymidine-labelled notochord cells, however, is higher in vitro than in vivo. At the same time, there is an age-dependent increase in pyknosis in the notochord in vivo and in vitro. So, during the aging process, the number of both pyknotic nuclei and of [³H]thymidine-labelled nuclei suggest a high turnover of notochord cells in vitro. From these results, we can conclude that the process of involution in aging notochord seems to be controlled by a programmed intrinsic process, which might be influenced partially by the microenvironment in vivo.     

Opioids and cytosolic calcium in rat anterior pituitary: dynorphin preparation showed LHRH-like action due to contamination

The effect of dynorphin A-(1-13) (Dyn A-(1-13] and other opioids on the cytosolic free calcium concentration [(Ca2+]i) in rat anterior pituitary cells was examined using the fluorescent indicator fura-2. A commercial synthetic Dyn A-(1-13) preparation elevated [Ca2+]i. Results, which were obtained with receptor antagonists, and in LHRH receptor radioligand binding studies as well as by HPLC combined with LHRH radioimmunoassay, strongly suggest that this effect of the dynorphin preparation was due to contamination with a LHRH-like compound. Dyn A-(1-13), purified by HPLC, as well as Dyn A-(2-13), [Leu5]enkephalin, beta-endorphin, morphine, or U50,488H had no effect on [Ca2+]i. LHRH caused a rapid increase in [Ca2+]i by about 50 nM which was blocked by the LHRH antagonist, [D-pGlu1,D-Phe2,D-Trp3,6] LHRH.     

Competitive inhibitors of neurohypophyseal hormones on adenylate cyclase from the toad urinary bladder

Zusammenfassung Adenylat-Cyclase in plasmamembranreichen Präparationen des Epitheliums von der Harnblase der Kröte wird durch Arginine-Vasopressin aktiviert. Diese Aktivierung wird durch mehre Oxytocinanaloge, die alle eine Substitution des Glutaminrestes in Position 4 des Hormones durch Leucin oder Isoleucin gemeinsam haben, kompetitiv gehemmt. Der stärkste Antagonist der Serie ist [2,4-diisoleucin]-Oxytocin und die antagonistische Aktivität nimmt in der Reihenfolge [4-Leucin]-, [2-Isoleucin-4-leucin]-, [2,4-Dileucin]- und [2-Phenylalanin-4-leucin]-Oxytocin ab. Die Resultate werden an Hand der Oxytocinkonformation diskutiert.

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Supported by United States Public Health Service grants No. AM-13567 (RW), by the Life Sciences Foundation, Inc., and by the National Science Foundation No. GB-30716X (VJH).

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Neurohypophyseal hormone analogs are denoted in accordance with the IUPAC-IUB [Tentative Rules (Biochemistry6, 362, 1967)].     

Pharmacological studies of a new analgesic, dl-erythro-1-phenyl-2-(o-chlorophenyl)-2-[4-(p-methoxybenzyl)-1-piperazinyl] ethanol dihydrochloride, in experimental animals.

dl-Erythro-1-phenyl-2-(o-chlorophenyl)-2-[4-(p-methoxybenzyl)-1-piperazinyl] ethanol dihydrochloride showed orally a definite analgesic activity, without producing the significant morphine-like physical dependence liability, and its analgesic potency was about a half that of codeine and far superior to aminopyrine in experimental animals.     

Pharmacological studies of a new analgesic,dl-erythro-1-phenyl-2-(o-chlorophenyl)-2-[4-(p-methoxybenzyl)-1-piperazinyl] ethanol dihydrochloride,in experimental animals

Summary dl-Erythro-1-phenyl-2-(o-chlorophenyl)-2-[4-(p-methoxybenzyl)-1-piperazinyl] ethanol dihydrochloride showed orally a definite analgesic activity, without producing the significant morphine-like physical dependence liability, and its analgesic potency was about a half that of codeine and far superior to aminopyrine in experimental animals.     

Preparation of a new synthetic dehydrorotenoid

Zusammenfassung Eine einfache Synthese eines Dehydrorotenoids 1,2-Dihydro-2-methyl-12H-[1]benzopyrano [3,4-b] furo [2,3-h] [1] benzopyran-6-on aus Desoxybenzoin Derivat wird beschrieben.     

Fatty acid modulation of antiestrogen action and antiestrogen-binding protein in cultured lymphoid cells

Nonsteroidal antiestrogens reversibly and specifically inhibited the proliferation of two estrogen receptor-negative lymphoid cell lines (EL4 and Raji) in a dose-dependent manner. [3H]Thymidine incorporation of concanavalin A-stimulated primary splenocytes was also inhibited by 10(-6) M clomiphene (1-[4-(2-diethylaminoethoxy)phenyl]-1,2-diphenyl-2-chloroethylene). The antiproliferative effect could be prevented by the simultaneous presence in the growth medium of 10(-5) M linoleic acid or 10(-5) M arachidonic acid but not by 10(-6) M estradiol. Both lymphoid cell lines had high affinity antiestrogen-binding sites whose affinity could be altered by conditions of growth. Growth of EL4 cells in RPMI 1640 medium supplemented with charcoal-pretreated 5% fetal calf serum (charcoal-stripped medium) resulted in significantly higher affinity (Kd 0.54 nM +/- 0.11 nM; n = 6) than growth in medium supplemented with untreated serum (complete medium) (Kd = 1.68 nM +/- 0.48 nM; n = 6) (p less than 0.001). This change in affinity was partly due to removal of fatty acids from the growth medium by charcoal pretreatment, since addition of 10(-5) M linoleic acid or 10(-5) M gamma-linolenic to charcoal-stripped medium decreased the affinity of the antiestrogen-binding protein. In contrast, growth in 10(-5) M stearic acid or 10(-5) M oleic acid did not significantly alter the affinity of the antiestrogen-binding protein, whereas 10(-5) M palmitic acid significantly increased its affinity. The same fatty acids were also tested for their intrinsic effects on EL4 cell proliferation. Oleic, linoleic and gamma-linolenic acids were growth stimulatory while stearic and palmitic acids were not. Thus linoleic and gamma-linolenic acids whose presence in the growth medium was associated with decreased affinity of [3H]tamoxifen (1-[4-(2-dimethylaminoethoxy)phenyl]-1,2-diphenylbut-1(Z)-ene) binding to the intracellular antiestrogen-binding protein were also growth stimulatory. Unsaturated fatty acids have previously been shown to inhibit binding of [3H]tamoxifen to the antiestrogen-binding protein in a cell-free system. The present observations demonstrate that unsaturated fatty acids also modify the affinity of the antiestrogen-binding protein in intact cells.