Application of NMR to Stereochemistry. (I). The Spatial Interaction Effect of the Hydroxyl Group to Methyl Resonance.(< ?? ?? >53)

Formation of 6 beta-OH-deoxycorticosterone from deoxycorticosterone by A6 cells

We have investigated the metabolism of deoxycorticosterone in A6 cells, a continuous cell line derived from the kidney of Xenopus laevis. A6 cells at confluence were incubated with serum-free culture media containing 2.5 microM [3H] deoxycorticosterone. When radioactive compounds in incubation media were separated by reverse-phase high-pressure liquid chromatography, the formation of polar metabolites was observed. One component of polar metabolites cochromatographed with 6 beta-hydroxydeoxycorticosterone. In order to identify this component more rigorously, large scale cultures were performed and this compound was separated and purified by reverse-phase high-pressure liquid chromatography. The purified material was analyzed by gas chromatography-mass spectrometry, secondary ion mass spectrometry, and nuclear magnetic resonance spectroscopy. These procedures revealed that this material was 6 beta-hydroxydeoxycorticosterone.

Identification of aldosterone metabolites formed by A6 cells

The A6 cell line of the toad kidney is well known to form an Na+ transporting tight epithelium in culture and is often used as an experimental model for Na+ transport systems. Although it has been shown that A6 cells can convert aldosterone to polar metabolites, these metabolites have not been identified. Therefore, in this study, we tried to identify the metabolites of aldosterone formed by A6 cells in culture. A6 cells at confluence were incubated with serum-free culture media containing [3H]aldosterone. When radioactive compounds in incubation media were separated by reversed phase high-pressure liquid chromatography (HPLC), four fractions (fractions A-D) were obtained. Fraction A, a mixture of two components, comprised the majority of metabolites formed. The more polar material (fraction A-1) and the less polar material (fraction A-2) of fraction A contained 47-71 and 9-19% of total radioactivity, respectively. When incubated in cell-free media, fraction A-2 was found to be unstable and partially converted to fraction A-1. Fraction B, 0.7-1.5% of total radioactivity, and fraction C, 8-21% of total radioactivity, cochromatographed with iso-aldosterone and D-aldosterone, respectively. Fraction D, 4-8% of total radioactivity, was a mixture of two components, which cochromatographed with 3 beta,5 beta-tetrahydroaldosterone and 5 alpha-dihydroaldosterone, respectively. In order to identify fraction A-2 material, large-scale cultures were performed and fraction A-2 was separated and purified by reversed phase HPLC. The purified material was analyzed by fast atom bombardment mass spectrometry and nuclear magnetic resonance spectroscopy. These two procedures unambiguously revealed that this material was 6 beta-hydroxyaldosterone. These results demonstrate that aldosterone can be converted to at least four metabolites by the incubation with A6 cells, and that major metabolites are polar compounds, a portion of which is 6 beta-hydroxyaldosterone.

Identification and quantification of 6 beta-hydroxydexamethasone as a major urinary metabolite of dexamethasone in man

Identification of 6 beta-hydroxydexamethasone as a major urinary metabolite of dexamethasone in man has been accomplished by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. Mass fragmentographic measurements revealed that more than 30% of the intravenously or orally administered dexamethasone dose was excreted in the 24-h urine as 6 beta-hydroxydexamethasone, while only a small fraction of the dose was excreted as unchanged dexamethasone and its glucuronic acid conjugate.

Syntheses of 15 alpha- and 15 beta-carboxymethyltestosterone bovine serum albumin conjugates: characteristics of the antisera to testosterone

Syntheses of 15 alpha- and 15 beta-carboxymethyltestosterone (15 alpha- and 15 beta-CMT) were investigated in order to prepare testosterone-bovine serum albumin conjugates for radioimmunoassays of testosterone. A mixture of 15 alpha- and 15 beta-bis(ethoxycarbonyl)methyl-3 beta-hydroxy-5-androsten-17-one (IIa and IIb) obtained by a reaction of 3 beta-hydroxy-5,15-androstadien-17-one (I) and sodium diethyl malonate was oxidized to afford a mixture of 15 alpha- and 15 beta-bis(ethoxycarbonyl)methyl-4-androstene-3, 17-dione (Va and Vb). After the separation by silica gel chromatography, each epimer obtained was hydrolyzed by acid, followed by decarboxylation, and selective reduction of the 17-ketone to give 15 alpha- and 15 beta-CMT. The antisera, generated in rabbits by immunization with the bovine serum albumin (BSA) conjugates of 15 alpha- and 15 beta-CMT, respectively, exhibited high specificity for testosterone.