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5 Nucleotidase

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M Le Hir – One of the best experts on this subject based on the ideXlab platform.

  • Distribution of ecto-5′-Nucleotidase in the rat liver: effect of anaemia
    Histochemistry, 1994
    Co-Authors: T. C. Schmid, M Le Hir, Johannes Loffing, Brigitte Kaissling

    Abstract:

    In the kidney a striking parallel exists between the expression of ecto-5′-Nucleotidase and of erythropoietin by renal fibroblasts. It was therefore hypothesized that the expression of ecto-5′-Nucleotidase in fibroblasts might be controlled by oxygen tension. In order to test this hypothesis, we examined the distribution of the enzyme in a tissue which displays a defined zonation in respect to oxygen tension, namely in the liver; anaemia was used in order to exaggerate this zonation. The distribution of ecto-5′-Nucleotidase was investigated by light and electron microscopy using enzyme and immunohistochemical methods in the livers of healthy and of anaemic rats. Anaemia was produced by haemolysis combined with X-ray irradiation. The enzyme was detected in the bile canaliculi, in the connective tissue of the portal triads and of the central veins, and in fat-storing cells probably corresponding to a special form of fibroblasts. In healthy animals the perisinusoidal ecto-5′-Nucleotidase activity was slightly higher in the pericentral than in the periportal area of the acinus whereas the inverse was observed for the staining of bile canaliculi. Anaemia provoked an increase of ecto-5′-Nucleotidase in fat-storing cells in the pericentral zone of the acinus and in fibroblasts around the central veins, resulting in steepended gradients along the sinusoids. The intralobular gradient of ecto-5′-Nucleotidase in perisinusoidal cells and the effect thereon of anaemia suggest that the expression of the ecto-5′-Nucleotidase might be directly or indirectly controlled by local oxygen tension.

  • Distribution of ecto-5‘-Nucleotidase in the rat liver : effect of anaemia
    Histochemistry, 1994
    Co-Authors: T. C. Schmid, M Le Hir, Johannes Loffing, Brigitte Kaissling

    Abstract:

    In the kidney a striking parallel exists between the expression of ecto-5′-Nucleotidase and of erythropoietin by renal fibroblasts. It was therefore hypothesized that the expression of ecto-5′-Nucleotidase in fibroblasts might be controlled by oxygen tension. In order to test this hypothesis, we examined the distribution of the enzyme in a tissue which displays a defined zonation in respect to oxygen tension, namely in the liver; anaemia was used in order to exaggerate this zonation. The distribution of ecto-5′-Nucleotidase was investigated by light and electron microscopy using enzyme and immunohistochemical methods in the livers of healthy and of anaemic rats. Anaemia was produced by haemolysis combined with X-ray irradiation. The enzyme was detected in the bile canaliculi, in the connective tissue of the portal triads and of the central veins, and in fat-storing cells probably corresponding to a special form of fibroblasts. In healthy animals the perisinusoidal ecto-5′-Nucleotidase activity was slightly higher in the pericentral than in the periportal area of the acinus whereas the inverse was observed for the staining of bile canaliculi. Anaemia provoked an increase of ecto-5′-Nucleotidase in fat-storing cells in the pericentral zone of the acinus and in fibroblasts around the central veins, resulting in steepended gradients along the sinusoids. The intralobular gradient of ecto-5′-Nucleotidase in perisinusoidal cells and the effect thereon of anaemia suggest that the expression of the ecto-5′-Nucleotidase might be directly or indirectly controlled by local oxygen tension.

  • A soluble 5‘-Nucleotidase in rat kidney. Stimulation by decavanadate.
    Biochemical Journal, 1991
    Co-Authors: M Le Hir

    Abstract:

    A soluble 5′-Nucleotidase was identified in rat kidney and partially purified. Compared with 5′-IMP, 5′-AMP was a poor substrate. The affinity for 5′-IMP was very low (S0.5 greater than 1 mM) in the absence of an activator, and it was much increased (S0.5 = 0.1 mM) by 2,3-bisphosphoglycerate (2,3-DPG). ATP and bisadenosyl tetraphosphate were further activators. The pH optimum was 6.3. Those properties suggest that the renal soluble 5′-Nucleotidase is identical with the ‘high-Km’ 5′-Nucleotidase purified previously from liver, heart and erythrocytes. Decavanadate (100 nM) increased the rate of hydrolysis of 1 mM-5′-IMP 16-fold. The effect was specific for the decameric form of vanadate, since it was not reproduced by either decavanadate-free orthovanadate or pervanadate. Half-maximal activation was obtained at 1.4 nM-decavanadate. Decavanadate increased the affinity of the soluble 5′-Nucleotidase for 5′-IMP. The effects of 2,3-DPG and of vanadate were not additive. Thus decavanadate probably influences the soluble 5′-Nucleotidase in the same way as 2,3-DPG, but with a much higher potency.

Tsutomu Araki – One of the best experts on this subject based on the ideXlab platform.

  • Plasma 5‘-Nucleotidase activities increase in women with hyperemesis gravidarum.
    Clinical biochemistry, 2002
    Co-Authors: Yoshio Yoneyama, Yasuo Otsubo, Hajime Kobayashi, Makiko Kato, Hiromitsu Chihara, Takashi Yamada, Tsutomu Araki

    Abstract:

    Abstract Objectives To investigate plasma activities of 5′-Nucleotidase, a key enzyme in the production of adenosine and evaluate the relationship between changes in 5′-Nucleotidase activities and pregnancy-related hormones, estrogen, progesterone and human chorionic gonadotropin (hCG) in women with hyperemesis gravidarum. Design and methods Plasma 5′-Nucleotidase activities and estradiol, progesterone and hCG levels were measured in 21 women with hyperemesis gravidarum and normal pregnancies, matched for age, parity and gestational week. Results In women with hyperemesis gravidarum, plasma 5′-Nucleotidase activities averaged 8.1 ± 0.6 IU/L, which were significantly increased compared to those in normal pregnant women (5.5 ± 0.5 IU/L)( p Conclusions The increase of plasma 5′-Nucleotidase activities may be at least partly attributed to elevations of pregnancy-related hormones, suggesting changes in purine metabolism in women with hyperemesis gravidarum.

Yoshio Yoneyama – One of the best experts on this subject based on the ideXlab platform.

  • Plasma 5‘-Nucleotidase activities and uric acid levels in women with pre-eclampsia.
    Gynecologic and obstetric investigation, 2002
    Co-Authors: Yoshio Yoneyama, Shunji Suzuki, Rintaro Sawa, Yasuo Otsubo, Atsushi Miura, Yoshimitsu Kuwabara, Hiroshi Ishino, Yasuko Kiyokawa, Daisuke Doi, Koichi Yoneyama

    Abstract:

    The present study investigated plasma activity of 5‘-Nucleotidase, a key enzyme in the production of adenosine, in pre-eclampsia, and evaluated the relationship between changes in 5‘-Nucleotidase activity, and levels of uric acid, endproduct of the purine metabolism, and the severity of pre-eclampsia. We measured plasma 5‘-Nucleotidase activities and uric acid levels in women with 18 normal pregnancies, mild and severe pre-eclampsia. In mild and severe pre-eclampsia, plasma 5‘-Nucleotidase activities and uric acid levels were significantly increased compared with those in normal pregnancy (p < 0.05). Plasma 5‘-Nucleotidase activity increased according to increases in uric acid levels and the severity of pre-eclampsia. These results suggest that increased plasma 5‘-Nucleotidase activity may, at least in part, be related to changes in purine metabolism in pre-eclampsia.

  • Plasma 5‘-Nucleotidase activities increase in women with hyperemesis gravidarum.
    Clinical biochemistry, 2002
    Co-Authors: Yoshio Yoneyama, Yasuo Otsubo, Hajime Kobayashi, Makiko Kato, Hiromitsu Chihara, Takashi Yamada, Tsutomu Araki

    Abstract:

    Abstract Objectives To investigate plasma activities of 5′-Nucleotidase, a key enzyme in the production of adenosine and evaluate the relationship between changes in 5′-Nucleotidase activities and pregnancy-related hormones, estrogen, progesterone and human chorionic gonadotropin (hCG) in women with hyperemesis gravidarum. Design and methods Plasma 5′-Nucleotidase activities and estradiol, progesterone and hCG levels were measured in 21 women with hyperemesis gravidarum and normal pregnancies, matched for age, parity and gestational week. Results In women with hyperemesis gravidarum, plasma 5′-Nucleotidase activities averaged 8.1 ± 0.6 IU/L, which were significantly increased compared to those in normal pregnant women (5.5 ± 0.5 IU/L)( p Conclusions The increase of plasma 5′-Nucleotidase activities may be at least partly attributed to elevations of pregnancy-related hormones, suggesting changes in purine metabolism in women with hyperemesis gravidarum.