Search results for "metyrapone"
showing 8 items of 18 documents
Experiments on the metyrapone reducing microsomal enzyme system.
1970
The formation of reduced metyrapone [2-methyl-1.2-bis-(3-pyridyl)-1-propanol] from metyrapone [2-methyl-1.2-bis-(3-pyridyl)-1-propanone] in the liver has been studied. Reduced metyrapone appeared as the main metabolite of metyrapone in the isolated perfused rat liver. Experiments on the intracellular distribution of the metyrapone reducing activity revealed that metyrapone reductase is mainly localized in the microsomal fraction. In the 105,000 × g supernatant only a little activity was found.
�ber die Wirkung von Metyrapon auf den mikrosomalen Arzneimittelabbau
1967
The inhibitor of adrenal steroid-11-β-hydroxylation, Metyrapone (SU 4885), also decreases the rate of drug hydroxylation reactions, both in vitro and in vivo. The follwing oxidative microsomal reactions were studied: O-demethylation of p-nitroanisole, N-demethylation of amidopyrine, and ring hydroxylation of acetanilide. In all three cases Metyrapone inhibits the formation of the reaction products. The inhibitor concentrations required for reduction of the initial reaction rates to one half are 7.5 · 10−4 M, 5 · 10−4m and 20 · 10−4 M, respectively. Steroid C-11-β-hydroxylation is reduced to one half by 2.5 · 10−4 M Metyrapone.
Zur Wirkung von Angiotensin II auf die Nebennierenrinde bei Blockade der 11-β-Hydroxylierung
1964
Tierexperimentell wird der von uns beobachtete Bremseffekt des Angiotensin II auf die unter Metopiron erhohte ACTH-Ausschuttung der Hypophyse untersucht.
Unexpected adverse effect of metyrapone: A case report
2018
Influence of hydrocortisone on chick embryo retina development
1987
Treatment of chick embryos in ovo with hydrocortisone-21-phosphate (a single dose of 150 micrograms) caused a marked reduction of retinal thymidine kinase activity 24 h later. The inhibitory effect was highest (65-70%) in 8-10-day-old embryos and declined with age, disappearing after day 15. It was accompanied by a reduction in thickness of the retinal layers. Adrenocorticotropic hormone (ACTH) treatment (10 micrograms daily for 2 days) also produced an age-dependent inhibitory effect on retinal thymidine kinase, whereas treatment with a single dose of 200 micrograms of metopirone, a compound that prevents the 11 beta-hydroxylation of steroid molecules in the adrenal glands, impeded the dec…
SEX DIFFERENCES IN THE PATTERN OF CYTOCHROMES P-450 IN RAT LIVER MICROSOMES
1977
ABSTRACT A number of sex differences in the spectral and enzymic properties of rat liver microsomes have been observed which may reflect differences in the population of hepatic cytochromes P 450 of male and female rats: 1. a blue shift in the spectrum of the reduced P 450-CO complex in females as compared to males, 2. lower ΔA max values in the binding of metyrapone to reduced microsomes in females as compared to males, 3. a higher proportion of 2-hydroxylation in the metabolism of biphenyl in females as compared to males, 4. preferential inhibition of ethoxycoumarin deethylation, benzpyrene hydroxylation and biphenyl-4-hydroxylation by α-naphthoflavone in females but by metyrapone in male…
Degradation of an alkaloid pheromone from the pale-brown chafer, Phyllopertha diversa (Coleoptera: Scarabaeidae), by an insect olfactory cytochrome P…
1999
AbstractThe pale-brown chafer, Phyllopertha diversa, utilizes an unusual alkaloid, 1,3-dimethyl-2,4-(1H,3H)-quinazolinedione, as its sex pheromone. This compound is rapidly degraded in vitro by the antennal protein extracts from this scarab beetle. Demethylation at the N-1 position and hydroxylation of the aromatic ring have been identified as the major catabolic pathways. The enzyme responsible for the pheromone degradation is membrane-bound, requires NAD(P)H for activity and is sensitive to cytochrome P450 inhibitors, such as proadifen and metyrapone. The ability to metabolize this unusual pheromone was not detected in 12 species tested, indicating that the P450 system, specific to male P…