Dopamine-β-Hydroxylase activity in serum of developing rats

Summary After birth, the activity of dopamine--hydroxylase in rat serum increased up to 14 days maximal level and decreased gradully to reach a low level at 42 days which was about 14% of the activity of maximal activity at 14 days.     

β-alanine and α-L-alanine inhibit the exploratory activity of spontaneously hypertensive rats

Summary 1% -alanine and -L-alanine, when given for 7 days as the only drinking fluid, inhibited the exploratory activity of adult male spontaneously-hypertensive rats (SHR)_but not that of the normotensive Wistar-Kyoto rats (WKR). -Alanine decreased the taurine level in the liver of both strains and in the platelets of SHR. -Alanine decreased the taurine level in the liver of WKR and in the platelets of SHR.This study was supported by the Sigrid Jusélius Foundation.     

Changes in dopamineβ-hydroxylase activity of monkey plasma with age

Summary Plasma dopamine -hydroxylase activity of Japanese monkeys (Macaca fuscata fuscata) increased with age, and the developmental changes were similar to those of human beings. However, the adult level plasma DBH activity of various monkey species was much lower than that of human beings.We thank Dr.K. Nozawa, Dr.O. Takenaka and Mr.T. Shotake (Primate Research Institute, Kyoto University) for their help in collecting monkey blood samples.     

Elevation of plasma dopamine-β-hydroxylase activity during insulin-induced hypoglycemia in man

Résumé Nous avons étudié l'activité de la dopamine--hydroxylase du plasma humain. Elle a été remarquablement accure par l'administration de grandes quantités d'insuline. Les corrélations entre cette activité et celle des systèmes nerveux sympathiques sont également discutées.     

Correlation between serum dopamine-β-hydroxylase activity and dopamine-β-hydroxylase and tyrosine hydroxylase activities in central and peripheral adrenergic neurons and adrenal glands

Summary Serum dopamine--hydroxylase activity in spontaneously hypertensive rats and Wistar-Kyoto rats had a positive correlation with dopamine--hydroxylase and tyrosine hydroxylase activities in mesenteric vessels, vas deferens, and adrenal glands at 14–16 weeks of age, a negative correlation with dopamine--hydroxylase activity in locus coeruleus at 3 weeks and 14–16 weeks of age, and a positive correlation with tyrosine hydroxylase activity only at 3 weeks of age, but not at 14–16 weeks of age.     

Hepatic cyclophorase activity in rats treated with 1,2,3,4-tetrahydro-β-naphtylamine (THNA)

Riassunto Gli omogenati di fegato dei ratti sacrificati dopo 4 h dalla somministrazione di-tetraidronaftilammina (30 mg pro kg per via intraperitoneale) presentano una aumentata capacità di ossidare alcuni composti del Ciclo di Krebs, in rapporto ai controlli. Viene avanzata l'ipotesi che l'intensa glicogenolisi epatica e muscolare e l'aumentata acetilazionein vivo dell'acido para-aminobenzoico provocate nel ratto dalla somministrazione di-tetraidronaftilammina, siano causate da un esaltato metabolismo intermedio ossidativo.     

Adrenal dopamine-β-hydroxylase activity: 24-hour rhythmicity and evidence for pineal control

Summary Adrenal medullary dopamine--hydroxylase activity was found in male rats to have a 24-hour rhythm, with an approximately 6-fold increase at about the time of the onset of darkness. This nocturnal rise in enzyme activity did not occur when lights were kept on, nor did it occur in animals that had been pinealectomized.Supported in part by grants from the Ford Foundation (No. 630-05050A), National Institutes of Health (No. HD-03352) and National Institute of Mental Health (No. MH-25019) USPHS.     

Dopamine-β-hydroxylase,adrenaline, noradrenaline and dopamine in the venous blood of adrenal gland of man: A comparison with levels in the periphery of the circulation

Summary In 10 human subjects plasma dopamine--hydroxylase activity was found in the adrenal vein blood to be as high as in the periphery of the circulation. Adrenaline concentration in the adrenal vein blood was in the mean 170 times, noradrenaline concentration 11 times and dopamine concentration little higher than levels in the periphery.This study was supported by the Deutsche Forschungsgemeinschaft.     

Increase in cystathionine β-synthase activity in the liver of rats treated withl-ethionine

Résumé Une seule injection d'éthionine (400 mg/kg) provoque une augmentation significative de l'activité de la cystathionine -synthase du foie de rat. La méthionine empêche l'effect de l'éthionine, tandis que l'actinomycine D, le cycloheximide, la méthionine sulfoximine, la méthionine sulfona et l'ATP ne le modifient pas. In vitro, l'éthionine n'a aucune influence sur l'activité de la cystathionine synthase hépatique.

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This work was supported by the Serbian Medical Research Foundation.     

Erythrocyte catechol-O-methyltransferase and plasma dopamine-β-hydroxylase in human umbilical cord blood

Summary Plasma dopamine--hydroxylase enzymatic activity and immunoreactive protein levels in human umbilical cord blood are only about 2% as great as values in the blood of older subjects. Erythrocyte catechol-O-methyltransferase activity levels in umbilical cord blood are very similar to those in the blood of adult subjects.This work was supported in part by NIH grants NS 11014 and HL 17487-1. Dr Weinshilboum is an Established Investigator of the American Heart Association. We thank Luanne Wussow and the physicians and nurses of the Department of Obstetrics and Gynecology of the Mayo Clinic for their assitance with these studies.     

Human plasma dopamine-β-hydroxylase: Oxygen and thermal stability

Summary There are wide individual variations in the thermal stability of human plasma dopamine--hydroxylase (DBH). Thermal stability variations have proven of value in biochemical genetic studies of many enzymes. The development of DBH thermolability depends on the exposure of plasma to oxygen. This observation may help to elucidate the biochemical basis of the genetic regulation of DBH.This work was supported in part by NIH grants HL 17487 and NS 11014.     

A radioimmunoassay for dopamine-β-hydroxylase using a glass-bound antibody

Résumé Les auteurs décrivent une méthode radioimmunologique de dosage de la DH utilisant un anticorps lié de façon covalente à des billes de verre. La technique a été appliquée à la mesure de la DH dans les surrénales et différentes régions du cerveau de buf. Les principaux avantages de cette méthode sont sa relative facilité d'emploi, sa précision et sa haute spécificité.

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This work was supported by USPHS Grants Nos. MH-02717, NS-06801 and CA-02071 and NSF Grant No. GB-27603.Acknowledgements: The authors wish to express their appreciation for the technical assistance of Susan Kadner and William P. Vann.     

β-Adrenoceptor blocking drugs,heart rate and genetic hypertension development in rats

Summary In spontaneously hypertensive rats (SHRs) chronically treated during their growth with -adrenoceptor blocking drugs, no correlation was found between the reduction in heart rate and the prevention of genetic hypertension development.This work was supported by a grant from the Scientific Council of the Faculté de Médecine Paris-Sud (1978/754).     

The structure of human interferon-β: implications for activity

Interferons (IFNs) are potent extracellular protein mediators of host defence and homoeostasis. This article reviews the structure of human IFN-β (HuIFN-β), in particular in relation to its activity. The recently determined crystal structure of HuIFN-β provides a framework for understanding of the mechanism of differentiation of type I IFNs by their common receptor. Insights are generated by comparison with the structures of other type I IFNs and from the interpretation of existing mutagenesis data. The details of the observed carbohydrate structure, together with biochemical data, implicate the glycosylation of HuIFN-β, which is uncommon among type I IFNs, as an important factor in the solubility, stability and, consequently, activity of the protein. Finally, these structural implications are discussed in the context of the clinical use of HuIFN-β. Received 12 June 1998; received after revision 16 July 1998; accepted 16 July 1998     

The effect of D-6-methyl-8-[β-isopropylaminoethyl] ergoline-I on the lactation in nursing rats

D-6-Methyl-8-[-isopropylaminoethyl] ergoline-I [VÚFB-10726], beginning from the dose of 0.05 mg/kg p.o., suppresses lactation through the inhibition of prolactin secretion in nursing rats.     

Sertoli cells of adult rats in vitro. II. Effect of different steroid precursors on estradiol 17β-synthesis

Summary The estradiol 17-synthesis by ⁴ pathway has been studied in homogenous cultures of Sertoli cells isolated from adult rat testes. The data reported clearly demonstrate that progesterone, androstenedione, testosterone and estrone induce an increase of the estradiol 17-production.This work was partially supported by grants No. 77.01322.04 and No. 77.01958.04 from the Consiglio Nazionale delle Ricerche.The excellent technical assistance of Antonio Muller and Massimo Rosati is deeply appreciated.     

Influence of sex,developmental time and food onβ-N-acetylglucosaminidase activity in the rice weevilSitophilus oryzae L.

Summary The effects of some biological parameters on -N-acetylglucosaminidase activity have been investigated inS. oryzae. There is no significant influence of sex and developmental time on the enzyme activity level, which appears in contrast to be greatly influenced by food (wheat or sorghum). Sorghum contains competitive inhibitors which are almost completely removed after dialysis. Fasting relieves this inhibition very quickly, suggesting that inhibitors act directly at the gut level.     

Influence of cyproterone acetate on the activity ofβ-glucuronidase in the hypothalamus and cerebral cortex of the male mouse

Summary Daily s.c. injections of cyproterone acetate greatly decrease the protein content and-glucuronidase activity in the mouse hypothalamus. These effects are reversible and the recovery capacity of the animal seems to be inversely related to the duration of antiandrogenic treatment.Financial aid was given by CNR (finalized project Biologia della Riproduzione) and Ministry of Education. Thanks are also due to Prof. G. Chieffi for suggestions and to Mr R. Auriemma for maintenance of experimental animals.