Excretion of 2- and 3-monomethyl ethers of 2-hydroxyestrogens in healthy male volunteers

1996 ◽  
Vol 135 (2) ◽  
pp. 193-197 ◽  
Author(s):  
Markus Banger ◽  
Christoph Hiemke ◽  
Margitta Haupt ◽  
Rudolf Knuppen

Banger M, Hiemke C, Haupt M, Knuppen R. Excretion of 2- and 3-monomethyl ethers of 2-hydroxyestrogens in healthy male volunteers. Eur J Endocrinol 1996;135:193–7. ISSN 0804–4643 The formation of catecholestrogens by 2-and 4-hydroxylation of monophenolic estrogens represents a major route of estrogen metabolism. In vitro and in vivo studies on catecholestrogens have shown that 2-hydroxylated catecholestrogens are primarily inactivated by O-methylation, while O-methylation of 4-hydroxylated estrogen is of minor importance. In the present study the in vivo production of isomeric 2- and 3-monomethyl ethers of 2-hydroxyestrogens was measured in 12 healthy omnivorous male volunteers aged 51 ± 4 years. The sum of estrone and 17β-estradiol, 2-hydroxyestrogens (sum of 2-hydroxyestrone and 2-hydroxyestradiol), 4-hydroxyestrogens (sum of 4-hydroxyestrone and 4-hydroxyestradiol) and the sum of the isomeric monomethyl ethers of 2-hydroxyestrone and 2-hydroxyestradiol were measured in 24-h urinary samples. The determinations included hydrolysis of steroid conjugates, separation by chromatographic steps and final quantification by radioimmunoassay. The specificity of the antibodies enabled differentiation between the isomeric monomethyl ethers. The mean urinary excretion rates were 8.8 ± 2.9 μg/24 h for estrone plus estradiol, 5.2 ± 2.4 μg/24 h for the 2-hydroxyestrogens and 1.3 ± 0.5 μg/24 h for the 4-hydroxyestrogens. The 2- and 3-monomethyl ethers of the 2-hydroxyestrogens were found in all individuals, with excretion rates of 5.8 ± 2.6 μg/24 h for 2-methoxyestrogens and 3.6 ± 1.1 μg/24 h for 2-hydroxyestrogen-3-methyl ethers. The findings indicated that 2-hydroxyestradiol is metabolized in vivo by 2-O-methylation and, to a lesser extent, by 3-O-methylation. Markus Banger, Department of Psychiatry, University of Essen, Virchowstr. 174, 45147 Essen, Germany

1999 ◽  
Vol 19 (03) ◽  
pp. 112-114
Author(s):  
C. M. Kirchmaier ◽  
Dagmar Westrup ◽  
J. Graff ◽  
R. Mahnel ◽  
H. K. Breddin ◽  
...  

SummaryWe report on an in vivo interaction study between aspirin (ASA) and Clopidogrel in healthy male volunteers and on an in-vitro interaction of abciximab and the peptidomimetic GPIIb/IIIa-inhibitor SR121566A with blood from subjects of the in vivo-study. Ten healthy male volunteers were randomly assigned to two groups (N = 5). Group 1 started with ASA and group 2 with Clopidogrel. From day 4 to 8 subjects of both groups received combined treatment with ASA and Clopidogrel. Blood from volunteers was spiked with abciximab or SR121566A. Inhibitory effects of ASA and Clopidogrel on collagen- or ADP-induced platelet aggregation were not enhanced by the combination of both drugs. TRAP-induced fibrinogen binding was reduced under ASA to 69% (n.s.), and to 63% under Clopidogrel or Clopidogrel + ASA. CD62-expression was reduced to 66% by Clopidogrel (p <0.01 ), whereas ASA had no effect. A further significant reduction to 41 % (difference to clopidogrel/ASA alone p <0.01), was seen under combined treatment (day 8). ASA and Clopidogrel increased the effects of the GPIIb/IIIa-inhibitors on collagen (2 pg/ml)- and ADP (5 pM)-induced aggregation. Under treatment with ASA and Clopidogrel inhibitory effects of GPIIb/IIIa-inhibitors on fibrinogen binding were additive to changes seen with ASA/clopidogrel alone. No additional effect on CD62 was seen with either GPIIb/IIIa-inhibitor.


2020 ◽  
Vol 48 (10) ◽  
pp. 873-885
Author(s):  
Ulrike Glaenzel ◽  
Yi Jin ◽  
Regine Hansen ◽  
Kirsten Schroer ◽  
Gholamreza Rahmanzadeh ◽  
...  

Author(s):  
M Usman ◽  
M Ahmad ◽  
AU Madni ◽  
NAW Asghar ◽  
M Akhtar ◽  
...  

1999 ◽  
Vol 43 (6) ◽  
pp. 1494-1496 ◽  
Author(s):  
Yoshihito Niki ◽  
Shinsuke Watanabe ◽  
Sadao Tamada ◽  
Koichiro Yoshida ◽  
Naoyuki Miyashita ◽  
...  

ABSTRACT The effect of HSR-903, a new fluoroquinolone, on the concentration of theophylline in serum in healthy male volunteers was investigated. The concentration of theophylline in serum and the urinary excretion rates of theophylline on day 5 of concomitant dosing with HSR-903 tended to increase compared to those on day 4, when theophylline was given alone; however, the urinary excretion rates of 1-methyluric acid and 3-methylxanthine on day 5 of concomitant dosing with HSR-903 tended to decrease in comparison to those on day 4, when theophylline was given alone.


1997 ◽  
Vol 41 (6) ◽  
pp. 1319-1321 ◽  
Author(s):  
P E Rolan ◽  
A J Mercer ◽  
E Tate ◽  
I Benjamin ◽  
J Posner

Atovaquone is an antiprotozoal compound with good in vitro stability against metabolic inactivation. Previous human studies which did not involve radiolabelling had not accounted for a substantial proportion of the dose. The possible metabolism of atovaquone in men was examined in a radiolabelling study involving four healthy male volunteers. Radioactivity was eliminated almost exclusively via the feces. All radioactivity in plasma, urine, and feces was accounted for by atovaquone, with no evidence of metabolites. Radiolabelled atovaquone was administered to a patient with an indwelling biliary tube after surgery. Biliary radioactivity was approximately 10- to 40-fold higher than that in plasma and was accounted for by atovaquone. Atovaquone is not significantly metabolized in humans but is excreted into bile against a high concentration gradient.


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