Location of functional groups with the aid of mass spectrometry. XVI.--Mass spectra of trimethylsilylated androstan-3,16,17 beta-triols

Developments in residue assay and metabolism study of growth-promoters by mass spectrometric analysis

The French national reference laboratory, for the control of growth-promoter residues, has developed routine methods of multiresidue analysis. These are mainly for the determination of beta-agonistic and steroid compounds. Apart from this regulatory activity, some research into growth-premotor metabolism and assay has also been carried out. This research concerns the method development of assay and metabolism studies of new compounds, including in vitro metabolism studies on cell (mainly hepatocytes) cultures, as well as studying the organic synthesis of new compounds and metabolites. Three examples of the different areas of research are presented here: the metabolism study of 4-chlorotestosterone in cattle; a methodological study on beta-agonists assay by mass spectrometry; and a residue study of beta-agonists in edible tissues.

Comparison of the use of mass spectrometry and methylene unit values in the determination of the stereochemistry of estranediol, the major urinary metabolite of 19-nortestosterone in the horse

The stereochemistry of an isomer of 5-estrane-3,17 alpha-diol, the major metabolite of 19-nortestosterone in horse urine has been established by the use of methylene unit (MU) values. The empirical MU values of the bis-trimethylsilyl (TMS) derivatives of the eight available isomers of 5-androstane-3,17-diol and four isomers of 5-estrane-3,17 beta-diol were determined by capillary gas chromatography using three different columns. From this data the theoretical MU values for the bis-TMS derivatives of the four 5-estrane-3,17 alpha-diol isomers were predicted. Comparison of the experimentally determined MU value of the urinary metabolite with those of the theoretical values established the correct stereochemistry of the steroid. This method has been compared with the use of gas chromatography-mas spectrometry in the determination of the stereochemistry of unknown metabolites.

Biotransformation of 1-dehydrotestosterone in the equine male castrate: identification of the neutral unconjugated and glucuronic acid conjugated metabolites in horse urine

The in vivo biotransformation of (1,2(n)-3H)1-dehydrotestosterone was studied in three equine male castrates and a number of neutral metabolites were identified in the urinary unconjugated and glucuronic acid conjugate fractions by gas chromatography/mass spectrometry. The metabolites were extracted from aliquots of the 0-24 h urine samples by Amberlite XAD-2 and separated into combined unconjugated plus glucuronic acid conjugated and sulphoconjugated fractions by Sephadex LH-20 column chromatography. After enzymatic hydrolysis of the glucuronides, the crude neutral unconjugated steroids plus the aglycones were partially purified by Kieselgel H chromatography and identified as their methyloxime trimethylsilyl derivatives. In the unconjugated fraction, the major metabolites were isomers of androsta-1,4-diene-6,16,17-triol-3-one. In the aglycone fraction a small amount of the parent steroid was present but the major metabolite was the 17 alpha isomer androsta-1,4-dien-17 alpha-ol-3-one. Other metabolites containing the 1,4-dien-3-one group were isomers of androsta-1,4-diene-16,17-diol-3-one and androsta-1,4-diene-6,16-diol-3-one. Reduction of the 4-ene functionality leading to the formation of 5-androst-1-en-16-ol-3,17-dione, 5-androst-1-ene-16,17-diol-3-one and of the 1-ene functionality leading to the formation of testosterone and its further reduction leading to the formation of C19O2 and C19O3 androstane metabolites was observed. Some interesting features on the electron impact fragmentations of the methyloxime trimethylsilyl derivatives of steroids containing a 1,4-dien-3-one group were also observed.

Identification of a new Sertoli cell metabolite of testosterone: 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol, by HPLC and GC-MS

Testosterone metabolism by isolated rat Sertoli cells cultured in vitro was investigated using HPLC and GC-MS techniques. Monolayer cultures of Sertoli cells (greater than 90% pure and free of Leydig cells) were incubated for 3-day periods with a stable labeled [2,2,4,6,6-d5]testosterone prepared and used in a 1:1 proportion with unlabeled testosterone as the substrate (5 X 10(-7)M). After incubation, the metabolites were extracted from the media and reacted with oestradiol-antibodies. The antibody-bound components were separated on reverse phase HPLC and the fraction corresponding to oestradiol was analyzed by GC-MS in the form of TMS-ether. One of the metabolites whose mass spectrum contained d0 + d5 species was detected and interpreted to be a triol with a mol. wt of 308. Mass spectra data indicated that this testosterone metabolite is one of the sixteen possible isomers of 3,16,17-trihydroxy androstane. This substance was identified based on the Vm value (27.81) closely resembling that of 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol TMS-ether (Vm reported = 27.78) [1] and when compared directly with synthesized compounds [2-3]. Recently we have demonstrated that similar Sertoli cell preparations contain two 16 alpha-hydroxylases by their ability to convert oestradiol to oestriol [4] and 5 alpha-androstane-3 alpha,17 beta-diol to 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol [3], where the former conversion is not affected by FSH, the latter is significantly stimulated by the presence of FSH. Presence of this new product represents the first example of testosterone conversion to 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol and confirms our previous observation that 16 alpha-hydroxylation of 5 alpha-reduced androgens can occur in the rat testis.

Studies related to the metabolism of anabolic steroids in the horse: the identification of some 16-oxygenated metabolites of testosterone and a study of the phase II metabolism

1. Isomers of 3,17-dihydroxyandrostan-16-one, 3,16-dihydroxyandrostan-17-one and androstane-3,16,17-triol have been identified as urinary metabolites of testosterone in the horse. 2. Following XAD-2 extraction of urine samples, Sephadex LH-20 chromatography was used to separate the extract into conjugate groups. Metabolites obtained after hydrolysis of the conjugates have been investigated by g.l.c.-mass spectrometry. 3. Testosterone, 3,17-dihydroxyandrostan-16-one and 3,16-dihydroxyandrostan-17-one were found only in the sulphate fraction. 5 alpha-Androstane-3 beta,17 beta-diol, and two isomeric androstane triols were present mainly in this fraction and 5 alpha-androstane-3 beta,17 alpha-diol was a minor component. In the glucuronide fraction 5 alpha-androstane-3 beta,17 alpha-diol was the major metabolite present and 5 alpha-androstane-3 beta,17 beta-diol and the two isomeric triols were minor components.

Occurrence of highly oxygen-substituted androgens in hemofiltrates of uremic patients

The steroid fraction of hemofiltrate contains a large number of unknown steroids, which were separated by a combination of different chromatographic procedures and finally characterized by gas chromatography mass spectrometry. Besides different isomeric 3,16,17-trihydroxyandrostanes in a rather polar fraction a 3,16,17-trihydroxy-11-ketoandrostane was detected, obviously the first naturally occurring representative of 3,11,16,17-oxygen-tetrasubstituted androstanes.

Studies related to the metabolism of anabolic steroids in the horse: the identification of some 16-oxygenated metabolites of 19-nortestosterone

1. The metabolism of 19-nor[4-14C]testosterone in a thoroughbred horse has been studied and neutral urinary metabolites obtained after enzyme hydrolysis have been investigated by g.l.c.-mass spectrometry. 2. 3-Hydroxyestran-17-one, 17 alpha- and 17 beta-nortestosterone, estrane-3,17-diol (two isomers), 3,16-dihydroxyestran-17-one (two isomers), 3,17-dihydroxyestran-16-one (two isomers) and estrane-3,16,17-triol were identified in the neutral urinary extracts.