IN VITRO STOFFWECHSEL VON [4-14C]-TESTOSTERON IN VESICULARDRÜSEN VON RATTEN

1969 ◽  
Vol 62 (4) ◽  
pp. 747-752 ◽  
Author(s):  
Helmut R. Henrichs ◽  
Wilhelm Dirscherl
Keyword(s):  
Isotope Dilution ◽  
Seminal Vesicles ◽  
Dilution Technique ◽  
Isotope Dilution Technique ◽  
Chromatographic Behaviour

ABSTRACT Experiments to elucidate the in vitro metabolism of [4-14C] -testosterone in seminal vesicles of rats are described. Besides unchanged testosterone, the following metabolites were isolated and identified by their chromatographic behaviour: 3α,17β-dihydroxy-5α-androstan, androst-4-ene-3,17-dione, 17β-hydroxy-5α-androstan-3-one, 3β-hydroxy-5α-androstan-17-one, 5α-androstane-3,17-dione. The first 3 of these compounds were also identified by the inverse isotope dilution technique. The reduction in ring A yields 5α-metabolites only.

Evidence for the existence of a C25-sesterterpene pathway of steroidogenesis not involving cholesterol as an obligatory intermediate

1983 ◽  
Vol 61 (7) ◽  
pp. 714-721 ◽  
Author(s):  
Bhagu R. Bhavnani ◽  
Tony Wong
Keyword(s):  
Isotope Dilution ◽  
Guinea Pigs ◽  
Radiochemical Purity ◽  
Specific Activity ◽  
Dilution Technique ◽  
Isotope Dilution Technique ◽  
Alternate Pathway

Previous in vitro studies had indicated the possibility of steroidogenesis through a C25-sesterterpene pathway in which squalene and cholesterol are not required as obligatory intermediates. To investigate whether such a pathway exists in vivo, the precursor role of [7-3H]23,24-dinor-5-cholene-3β,20-diol in the in vivo formation of cortisol by the guinea pigs was studied. The [3H]23,24-dinor-5-cholene-3β,20-diol was synthesized by reacting [3H]pregnenolone acetate with a Grignard reagent. The product was purified by chromatography and its radiochemical purity was established by the isotope dilution technique. In the first experiment a total of 134 × 106 dpm of [3H]23,24-dinor-5-cholene-3β,20-diol was injected subcutaneously into three guinea pigs. Urine was collected for 8 days and was pooled. Only 12% of the administered dose was excreted in the urine. The urine was extracted and a neutral extract (3 × 106 dpm) was obtained. From this extract 2.3 mg of cortisol containing 2.9 × 104 dpm was isolated. Radiochemical purity of the isolated cortisol was established by the isotope dilution technique. Radiochemical purity was further confirmed by conversion to cortisol 21-acetate and subsequently to 11β-hydroxyandrost-4-ene-3,17-dione and recrystallization to constant specific activity. The results of this experiment were confirmed by repeating the experiment with a higher specific activity [3H]23,24-dinor-5-cholene-3β,20-diol. These results indicate that the C25-sesterterpene pathway is a possible in vivo alternate pathway of steroidogenesis, not involving either squalene or cholesterol as obligatory intermediates.

O-Methylierung von Adrenalin, 3.4-Dihydroxybenzoesäure und 6.7-Dihydroxycumarin in Sproßpilzen /O-Methylation of Epinephrine, 3,4-Dihydroxybenzoic Acid and 6,7-Dihydroxycoumarin in Yeasts

1976 ◽  
Vol 31 (9-10) ◽  
pp. 509-513 ◽  
Author(s):  
D Müller-Enoch ◽  
H Thomas ◽  
W Streng ◽  
W Ildfeuer ◽  
O Haferkamp
Keyword(s):  
Enzyme Activity ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Isotope Dilution ◽  
Dihydroxybenzoic Acid ◽  
Dilution Technique ◽  
Isotope Dilution Technique ◽  
Methyl Derivatives ◽  
Layer Chromatography ◽  
Methoxybenzoic Acid

Abstract In the yeasts C. albicans, C. tropicalis, and C. stellatoidea but not in C. krusei, R. rubra, and S. cerevisiae enzyme activity was found by which - as by the catechol-O-methyltransferase (EC 2.1.1.6) found in the liver - the O-methylation of epinephrine to metanephrine and paranephrine, of 3,4-dihydroxybenzoic acid to 4-hydroxy-3-methoxybenzoic acid and 3-hydroxy-4-methoxybenzoic acid, and of 6,7-dihydroxycoumarin to 7-hydroxy-6-methoxycoumarin and 6-hydroxy-7-methoxy-coumarin is catalysed. When the substrates 3,4-dihydroxybenzoic acid, or 6,7-dihydroxycoumarin or epinephrine were incubated in the presence of S-adenosyl-ʟ-[methyl-14C] methionine and S-adenosylmethionine hydrogensulfate with a 100 000 X g supernatant of C. albicans, C. tropicalis or C. stellatoidea the cor­responding O-methylethers were detected in the extracts of the incubation medium by thin-layer chromatography. Final identification of the isomeric radioactive O-methylethers obtained from 3,4-dihydroxy­ benzoic acid and 6,7-dihydroxycoumarin was performed after thin-layer chromatographic separation by the reversed isotope dilution technique. The radioactive m-and p-O-methyl derivatives from epinephrine were separated by thin-layer chromatography and then cleaved with periodate to the corresponding aldehydes which were also identified mainly by the reversed isotope dilution technique.

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