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Dexamethasone (DXM) is a synthetic adrenal corticosteroid with anti-inflammatory properties used for therapeutic purposes in a wide range of pathologies and of the most common corticosteroids used for anabolic purposes in beef cattle. It is proven that DXM induces histological changes, traceable as increasing fatty infiltration of the thymus associated with a concurrent decrease of the cortex-medulla ratio, so the histological examination of the thymus gland has been established as an indirect morphological biomarker. The aim of the present study is to compare thymus histology and DXM concentrations in biological fluids collected at slaughterhouse after 1 month of DXM treatment. Our findings demonstrate that a low dosage of DXM administered to 12 months-old-Chianina beef cattle induces severe thymic atrophy with concurrent reduction of the cortex/medulla ratio, demonstrable even when DXM residues are not found in serum and urine samples. It is worth to note that, at the slaughterhouse, DXM residues are detectable in bile samples, indicating the ability of this biological fluid to bio-concentrate the administered drug if compared to serum and urine. Therefore, bile could be candidates as new liquid matrix for the screening programs planned to contrast the illegal use of anabolic substances., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

The illicit use of dexamethasone as growth-promoting agent in animal breeding is still practiced within the EU constituting a health risk for meat consumers. An experimental study was developed to assess dexamethasone urinary excretion and tissue distribution (liver, kidney, and muscle) in male calves after therapeutic and growth-promoting administration. Urine and tissue samples collected from treated and untreated bovines were also investigated for the presence of other natural and synthetic corticosteroids (prednisolone, prednisone, hydrocortisone, and cortisone), in order to study a possible correlation with dexamethasone administration and to clarify prednisolone origin. Analyses were performed by a multi-residue LC-MS/MS method developed and validated according to the Commission Decision 2002/657/EC. The results confirm the rapid rate of dexamethasone urinary excretion, irrespective of the dosage, the duration and the route of administration, and the disappearance of cortisone and hydrocortisone during the treatment. Dexamethasone was distributed to the tissues where the elimination rate proceeded relatively slower as suggested by the presence of residues one month after the withdrawal of the therapeutic treatment. An increase in the number of positive findings for prednisolone, in association with higher levels of cortisone and hydrocortisone, was observed in urine samples collected from slaughterhouse rather than those collected at the farm. Prednisone residues were found only in one urine sample that showed the highest levels of prednisolone, hydrocortisone, and cortisone. The occurrence of prednisolone residues in urine and even in tissue samples confirms the endogenous nature of this molecule., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Natural and synthetic corticosteroids are widely used in veterinary medicine for their anti-inflammatory properties, but are also illegally used in animal breeding as growth-promoting agents: this latter application in livestock production has been banned within the European Union due to health concerns for the consumer. In this work urine samples collected from bovines experimentally treated with dexamethasone (0.4 mg of dexamethasone 21-disodium phosphate per capita/day for 20 consecutive days) and bovines bred under strictly controlled conditions were investigated for the presence of natural and synthetic corticosteroids, using a simple multi-residue liquid chromatography-tandem mass spectrometry method, developed and validated in accordance with the criteria of the Commission Decision 2002/657/EC. The aim of this work is to investigate the effect of a low dosage and long term dexamethasone treatment on the levels of endogenous corticosteroids in cattle and to evaluate the possible presence of prednisolone residues in bovines bred under strictly controlled conditions. Our findings confirm the high and rapid rate of dexamethasone urinary excretion. Dexamethasone treatment elicited an early reduction of hydrocortisone and cortisone, suggesting the disappearance of these two hormones as an indirect indicator of corticosteroid treatment in cattle. Prednisolone residues were found (concentration interval 0.4-1.4 ngmL(-1)) in urine samples collected from control bovines especially at the slaughterhouse, together with high levels of hydrocortisone and cortisone. Further studies are necessary to find out the reason of unexplained excretion of this hormone in urine samples of untreated bovines., (Copyright © 2011 Elsevier Inc. All rights reserved.)