Etiocholanolone glucuronide

Formation of sulfates [328] is relatively reversible. This may be due to the fact that the metabolic clearance rate [318] of sulfates is relatively low [389] and their renal excretion inefficient [4]. The conversion of dehydroepiandrosterone sulfate in vivo to androsterone and etiocholanolone glucuronide was demonstrated by Lieberman and co-workers, who administered isotopically labeled dehydroepiandrosterone sulfate and isolated labeled androsterone and etiocholanolone from glucuronicase-hydrolyzed urine [303]. Since in another study by Lieberman [174], the transconjugation from dehydroepiandrosterone sulfate to dehydroepiandrosterone glucuronide without free dehydroepiandrosterone intermediate was declared to be improbable, in vivo equilibrium between dehydroepiandrosterone sulfate and dehydroepiandrosterone seems probable [303]. 

Disposition in the Body. Testosterone is the androgenic hormone formed in the testes. In man, it is metabolised to 5a-androstane-3a,17)5-diol, androsterone, etiocholanolone, and 5a-androstene-3,17-dione. In the horse, the major metabolites are 5a-androstane-3)5,17a-diol, which is excreted in the urine as the glucuronide conjugate, and the 17)5-epimer which is excreted in the urine as the sulphate conjugate. 

Adrenal androgens also have a complex metabolic fate DHEA-S is formed in the adrenal cortex or by sulfokinases in the liver and kidney from DHEA and excreted by the kidney. DHEA and DHEA-S can be metabolized by 7a-and 16a-hydroxylases. 17p-Reduction of both compounds forms A -5-androstenediol and its sulfate. Androstenedione can be metabolized to androsterone after 3a- and 5a-reduction. 5P-Reduction results in the formation of etiocholanolone (see Eigure 51-7). These metabolites are conjugated to glucuronides and sulfates, which are then excreted in the urine. 

Buiarelli et al. (2004) extended the above analytical approach to many more related steroids when they published a method for the direct analysis of 15 urinary anabolic steroids in a single run, namely T, epitestosterone, dehydroepiandrosterone (DHEA), androsterone, etiocholanolone, their sulfates and their glucuronides (Figure 2,2), They extracted 2 mL of human urine by solid-phase extraction with methanol elution and reconstituted the residue in aqueous methanol in the presence of deuterated internal standards (da-epitestosterone glucuronide, [16,16,17-"H3 testosterone sulfate and [16,16,17-2H3]testosterone), then monitored, for example, mJz. 289-97 and 109 for T and epitestosterone, miz 367-97 for their sulfates, and m/z 463-113 and 287 for their glucuronides. The method does not achieve quantitation, but it allows the estimation of ratios, which makes it possible to monitor the urinary steroid profile, which is useful for monitoring the abuse of anabolic steroids. 

The saturated Cai compounds are then either conjugated with glucuronic acid and appear in urine as the glucuronides, or they are further broken down. The side chain is split off particularly easily from 17-hydroxy compounds. The products are 17-keto steroids, androsterone, etiocholanolone, and. others, which are also excreted as glucuronides (more rarely as sulfates). The amount of 17-keto steroids in urine can be estimated easily with Zimmermann s color reaction it is useful for the diagnosis of adrenal cortical activity. One should be aware, however, that only a part of the corticosteroid excretion is measured, together vith testosterone inactivation products. Normally, about 10-20 mg per day of 17-keto steroids are excreted. 

---