The Effect of Chronic Thallium Administration on Testicular Enzyme Activities in the Rat

1985 ◽  
pp. 332-333
Author(s):  
C. Gregotti ◽  
L. Formigli ◽  
A. Di Nucci ◽  
P. Poggi ◽  
C. Roccio ◽  
...  
Keyword(s):  
Enzyme Activities

High time resolution enzyme cytochemistry of rod outer segment

1990 ◽  
Vol 48 (3) ◽  
pp. 878-879
Author(s):  
Takuma Saito ◽  
Toshihiro Takizawa
Keyword(s):  
Enzyme Activities ◽  
Outer Segment ◽  
Rapid Change ◽  
High Time Resolution ◽  
Visual Cell ◽  
Enzyme Cytochemistry ◽  
Activation Effect ◽  
Rod Outer Segment ◽  
Enzymatic Cascades ◽  
Rapid Drop

Cells and tissues live on a number of dynamic metabolic pathways, which are made up of sequential enzymatic cascades.Recent biochemical and physiological studies of vision research showed the importance of cGMP metabolism in the rod outer segment of visual cell, indicat ing that the photon activated rhodopsin exerts activation effect on the GTP binding protein, transducin, and this act ivated transducin further activates phosphodiesterase (PDEase) to result in a rapid drop in cGMP concentration in the cytoplasm of rod outer segment. This rapid drop of cGMP concentration exerts to close the ion channel on the plasma membrane and to stop of inward current brings hyperpolarization and evokes an action potential.These sequential change of enzyme activities, known as cGMP cascade, proceeds quite rapidly within msec order. Such a rapid change of enzyme activities, such as PDEase in rod outer segment, was not a matter of conventional histochemical invest igations.

Tryptophan-Niacin Metabolism in Rat with Puromycin Aminonucleoside-Induced Nephrosis

2006 ◽  
Vol 76 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Yukari Egashira ◽  
Shin Nagaki ◽  
Hiroo Sanada
Keyword(s):  
Body Weight ◽  
Urinary Excretion ◽  
Enzyme Activities ◽  
Treated Group ◽  
Control Group ◽  
Puromycin Aminonucleoside ◽  
Low Level ◽  
Key Enzyme

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidneyα-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.

Effect of a constant supply of different nitrogen sources on protein and carbohydrate content and enzyme activities of Anabaena variabilis cells

1995 ◽  
Vol 95 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Andres P Sanz ◽  
Conrado Moreno-Vivian ◽  
Jose M. Maldonado ◽  
Agustin Gonzalez-Fontes
Keyword(s):  
Enzyme Activities ◽  
Nitrogen Sources ◽  
Carbohydrate Content ◽  
Anabaena Variabilis

d/l threo-methylphenidate enantiomers influence on catecholaminergic enzyme activities

2011 ◽  
Vol 44 (06) ◽  
Author(s):  
E Grünblatt ◽  
J Bartl ◽  
S Hofmann ◽  
A Borst ◽  
P Riederer ◽  
...  
Keyword(s):  
Enzyme Activities ◽  
Methylphenidate Enantiomers

REGULATION OF THE ACTIVITIES OF THE ENZYMES INVOLVED IN THE METABOLISM OF STEROID HORMONES IN RAT LIVER: THE EFFECT OF 19-NORTESTOSTERONE AND THE INFLUENCE OF CYPROTERONE ACETATE ON THE ACTION OF TESTOSTERONE AND 5α-DIHYDROTESTOSTERONE

1974 ◽  
Vol 77 (2) ◽  
pp. 287-297 ◽  
Author(s):  
Rüdiger Ghraf ◽  
Edmund Rodney Lax ◽  
Hanns-Georg Hoff ◽  
Herbert Schriefers
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Rat Liver ◽  
Enzyme Activities ◽  
Cyproterone Acetate ◽  
Hydroxysteroid Dehydrogenase ◽  
Seminal Vesicles ◽  
Normal Male ◽  
Steroid Hydroxylases ◽  
Drug Leads

ABSTRACT The androgens testosterone and 5α-dihydrotestosterone, the anabolic drug 19-nortestosterone and the anti-androgen cyproterone acetate were investigated with regard to their modifying action on the sexual differentiation of the activities of rat liver enzymes involved in steroid hormone metabolism. The activities of the enzymes (Δ4-5α-hydrogenase, 20-ketoreductase, 3α-and 3β-hydroxysteroid dehydrogenase, NAD- and NADP-dependent Δ4-3β-hydroxysteroid dehydrogenase, total steroid hydroxylases, 7α- and 16α-hydroxylase) were determined in cell-free liver fractions of male animals castrated on day 25 of life and killed on day 90; and of castrated animals which, from day 75 to 89 received daily sc injections (0.3 mg/100 g body weight) of the anabolic drug or the androgen only or in combination with cyproterone acetate (3 mg/100 g body weight). With the exception of 7α-hydroxylase castration leads to a feminization of the enzyme activity pattern. However, the degree of feminization varies from enzyme to enzyme. The administration of testosterone or of 5α-dihydrotestosterone reverses the effect of castration. With 5α-dihydrotestosterone activity values were reached which in some cases were significantly higher than those obtained with testosterone. Although both androgens restored the enzyme activities to the normal male values, neither androgen was able to compensate for the weight loss of the seminal vesicles in the dose administered. The administration of 19-nortestosterone in the same dose as testosterone is only 30 % as effective in restoring the weight loss of the seminal vesicles, but leads to identical activities of Δ4-5α-hydrogenase and of hydroxysteroid dehydrogenases as are found for testosterone. 19-Nortestosterone is without influence on the activities of total steroid hydroxylases and of 16α-hydroxylase. 16α-Hydroxylase is the only enzyme in which the activity enhancing effects of testosterone or of 5α-dihydrotestosterone can be completely blocked by the simultaneous administration of the anti-androgen cyproterone acetate. In all other enzyme activities the anti-androgen does not interfere with the effect of the androgens although it blocks their action on the weight restitution of the seminal vesicles by 60–70 %. 7α-Hydroxylase does not exhibit any androgen dependency. Neither castration nor the subsequent administration of the two androgens, or of the anabolic drug leads to any alterations in activity. However, it is interesting to note that the administration of cyproterone acetate does cause an increase in activity.

Thermoregulation, respiration quotient and key antioxidant enzyme activities in the liver and heart of rats under hypergravity stress

2004 ◽  
Vol 10 (1) ◽  
pp. 99-104
Author(s):  
Kh.K. Muradian ◽  
◽  
A.N. Timchenko ◽  
N.A. Utko ◽  
T.A. Badova ◽  
...  
Keyword(s):  
Antioxidant Enzyme ◽  
Enzyme Activities ◽  
Antioxidant Enzyme Activities ◽  
Respiration Quotient
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