Determination of polyamine oxidase activities in human tissues

Summary A very simple fluorometric assay for polyamine oxidase (PAO) in tissues, with N¹-monoacetylspermine as substrate, is described. The PAO was present in all human organs tested; it was highest in the liver, followed by the testis, kidney, spleen and small intestine.     

Distribution of polyamine oxidase activity in rat tissues and subcellular fractions

The activity of polyamine oxidase (PAO) in rat tissues, and its subcellular distribution, were assayed using a simple polarographic method. The highest PAO activity was measured in the liver and the lowest in the skeletal muscle. In liver, kidney and uterus the highest specific PAO activity was found in the light mitochondrial fraction. PAO was not found in the microsomal fraction except in the kidney.     

Distribution of polyamine oxidase activity in rat tissues and subcellular fractions.

The activity of polyamine oxidase (PAO) in rat tissues, and its subcellular distribution, were assayed using a simple polarographic method. The highest PAO activity was measured in the liver and the lowest in the skeletal muscle. In liver, kidney and uterus the highest specific PAO activity was found in the light mitochondrial fraction. PAO was not found in the microsomal fraction except in the kidney.     

Monoamine oxidase activities in human brain microvessels

Summary Microvessels can be easily isolated from human brain samples obtained at autopsy. Human frontal cortex MAO type A and B activities are similar in microvessel and microvessel-free preparations. In microvessels, enzyme activities and the ratio of MAO type A to type B vary among the areas studied and could selectively regulate the passage of certain amines through the blood vessel wall.Acknowledgment. The technical assistance of N. Gentile and the financial support by NIMH grant MH31156 is gratefully acknowledged.     

Isozymes of amine oxidase in human plasma and other tissues

Zusammenfassung Menschliche Plasmaaminooxydase, bestehend aus verschiedenen Isoenzymen, deren Hauptfraktion in zahl reichen untersuchten parenchymatösen Organen vorhanden ist, wurde mit der Stärkegelektrophorese und Sephadex Säulenchromatographie untersucht. Isoenzyme aus Gewebehomogenaten und Plasma unterscheiden sich.     

‘Tetrazolium oxidase’ identified with the heme-oxidases of human tissues

Résumé Des bandes blanches jusqu'ici mystérieuse, apparaissent quand on teint des traces électrophorétiques avec des réactions de tétrazolium pour faire apparaÎtre diverses enzymes. Ces bandes se révèlent comme étant de l'hémoglobine et d'autres hémo-protéines se trouvant dans le sérum et dans des parties du tissue qui arrÊtent la réduction du tétrazolium. Ces bandes peuvent donc troubler le dessin électrophorétique.     

Monoamine oxidase activity in tissues of spontaneously hypertensive rats

Summary Monoamine oxidase (MAO) activity was assayed both in central and peripheral blood vessels of spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar Kyoto rats (WKR). The activity of MAO in the brain and peripheral vasculature was essentially the same in both SHR and WKR. It can therefore be concluded that central and peripheral vascular MAO activity is not altered in the genetically hypertensive animals.     

Nephrin in human lymphoid tissues

When nephrin, the protein product of NPHS1, was cloned, it was proposed to be specific for the kidney glomerular podocytes. Recently, however, new reports have emerged verifying additional nephrin expression sites, particularly the insulin-producing β cells of the pancreas, as well as the central nervous system. In this study, we demonstrate nephrin expression in lymphoid tissues, specifically the tonsil, adenoid and lymph node. Nephrin mRNA expression levels were 4-fold higher in tonsils and adenoids than in thymus or B lymphocytes, and 20-fold higher than in T lymphocytes or monocytes, as shown by quantitative RT-PCR analysis. Anti-nephrin antibodies recognised a specific 165-kDa band in lysates of tonsil and adenoid. In immunofluorescence and immunohistochemichal stainings of adenoid and lymph node sections, nephrin-positive cells were detected in the germinal centres of the lymphoid follicles in a staining pattern typical for interdigitating cells. These results indicate a definite and additional presence of nephrin in lymphoid tissue. Received 17 October 2005; received after revision 22 November 2005; accepted 20 December 2005     

Occurrence of mitochondrial monoamine oxidase in human semen

Summary Mitochondrial monoamine oxidase (MAO) was found in human semen, showing its K_m and V_max values of 91.7 M and 290 pmoles/mg of protein/60 min, respectively, with kynuramine as substrate. A major part of the activity was due to type A MAO.     

Occurrence of mitochondrial monoamine oxidase in human semen.

Mitochondrial monoamine oxidase (MAO) was found in human semen, showing its Km and Vmax values of 91.7 microM and 290 pmoles/mg of protein/60 min, respectively, with kynuramine as substrate. A major part of the activity was due to type A MAO.     

Effects of female sex hormones on polyamine-oxidizing enzyme activities and polyamine concentrations in immature rat uterus and liver

17-estradiol (E₂) and progesterone (P) treatment of immature female rats (10 g/100 g body weight) respectively resulted in 1.38-fold (p<0.02) and 1.42-fold (p<0.02) increase in the uterine polyamine oxidase activity, and 2.45-fold (p<0.001) and 1.43-fold (p<0.02) increase in the uterine diamine oxidase activity, as compared to the controls. E₂ caused a 5-fold (p<0.05) and a 1.36-fold (p<0.05) increase in putrescine and spermidine concentration respectively in rat uterus. Increases of 1.7-fold (p<0.02) and 1.6-fold (p<0.05) in putrescine and spermine concentration were determined in the P-treated uterus, as compared to the controls. The spermidine/spermine ratio, which is regarded as an index of growth rate, was higher in the E₂-treated uterus and lower in the P-treated uterus than in the control uterus. No statistically significant hormonal effects were estimated in the immature liver. The data reported suggest the possibility of an involvement of polyamine-oxidizing enzymes in the modulation of polyamine concentrations in rat uterus by the female sex hormones.     

Developmental and ageing changes in aminopeptidase activities in selected tissues of the rat

Aminopeptidase activities, assayed as arylamidase activities, were investigated in selected tissues of 1, 6, 12 and 24-month-old rats. The enzyme activities were found to have a heterogeneous distribution and age-related changes were observed. The highest levels of soluble arginyl-aminopeptidase activity were detected in brain homogenate at all the studied ages, whereas membrane-bound activity presented the highest levels in brain and kidney in the four ages tested. Aspartyl-aminopeptidase activity was detected mainly in the particulate fraction of kidney at all four ages. In 1, 6 and 12-month-old animals, soluble aspartyl-aminopeptidase activity was also higher in the kidney than in the rest of the tissues, whereas in the group of 2-year-old rats, the highest levels were found in both kidney and liver. Age-related changes were observed in all the studied tissues and for all the assayed enzymatic activities. In general, the maximal levels were detected in both the youngest and the oldest animals, and the minimal ones in 6 and 12-month-old rats. However, in the adrenals, the soluble and membrane-bound arginyl-aminopeptidase activity was higher in 6-month and 2-year-old rats than in 1-month and 12-month-old rats. These changes may reflect the functional status of the susceptible endogenous substrates of aminopeptidases.