Presence of endogenous prednisolone in human urine

Abstract

The possibility of an endogenous presence of the glucocorticoid prednisolone has already been demonstrated in bovine and horse urine, with the aim of clarifying its origin in this matrix, which is used by official agencies for the control of illicit treatments. From this point of view, the endogenous nature of prednisolone could be a major topic in doping control of both amateur and professional human athletes. A study was therefore made on 34 human volunteers (13 males and 21 females; aged 22-62) to detect the presence of prednisolone in their urine by HPLC-MS(3). One of the volunteers underwent vernal allergy treatment with betamethasone for two subsequent years. An investigation was carried out with the aim of verifying if the suppression, and the circadian rhythm, of cortisol urinary levels could also apply to prednisolone. The results of the study show that prednisolone was present in the urine of all 34 volunteers, with a concentration very close to 100-times lower that of cortisol, with no dependence on gender. The same ratio (1/100) was observed in the prednisolone and cortisol levels detected during the 24h together with the suppression of prednisolone by betamethasone treatment. These data demonstrate the endogenous nature of low concentrations of prednisolone in human urine, and motivate further studies about the biosynthetic pathways of this corticosteroid and its relationship with stress in humans, as already described in cows.

Detection and characterization of prednisolone metabolites in human urine by LC-MS/MS

“…PRED had been detected endogenously in urine at concentrations 100 times lower than cortisol (around 0.5 ng/ml). [35] This fact explains the small signal for PRED and most of its metabolites in pre-administration samples. The normalized area ratios of all metabolites along time are depicted in Fig.…”

“…The optimized SRM method allowed the detection of PRED at a limit of detection around 0.1 ng/ml. PRED had been detected endogenously in urine at concentrations 100 times lower than cortisol (around 0.5 ng/ml) . This fact explains the small signal for PRED and most of its metabolites in pre‐administration samples.…”

Preliminary study on the presence of prednisolone in porcine urine and liver – How to distinguish endogenous from therapeutically administered prednisolone

“…Prednisolone has also been detected in urine samples from racehorses sampled at Italian racetracks, [7,8] with a contamination frequency of 78.5% and a mean concentration of 1 ng/ml. Several urine samples taken in the framework of the Belgian Residue Control Plan in 2011 and 2012 were found to contain prednisolone.…”

Annual banned‐substance review: analytical approaches in human sports drug testing

“…[157] For doping control laboratories, the main challenge concerning this class of compounds resides in the differentiation of natural/endogenous corticosteroids and their synthetic preparations, especially regarding cortisol and, as recently corroborated, the natural or artifact-derived occurrence of prednisolone in human urine. [158] In a study by Brooker et al, the possibility to detect oral cortisone acetate administrations by GC/C/IRMS was presented, targeting the main urinary metabolites tetrahydrocortisol, tetrahydrocortisone, 11β-hydroxy-A, 11β-hydroxy-E, 11-oxo-E, and pregnanediol as ERC. [60] In order to improve gas chromatographic properties by avoiding derivatization, the so-called oxidation approach with potassium dichromate was employed, converting tetrahydrocortisone and tetrahydrocortisol as well as 11-oxo-E and 11β-hydroxy-E to 5βandrostanetrione, thus requiring HPLC fractionation prior to oxidation and analysis by GC/C/IRMS.…”