INTRODUCTION Boldenone (1,4-androstadiene-3–one, 17-ol) (BOL) and boldione (1, 4-androstadiene-3,17-dione) (ADD) are chemical derivatives of testosterone, known as strong anabolics and low to moderate androgenic agents. ADD, the dione form of BOL, is a direct precursor of that anabolic steroid, and it is activated by the same widely distributed 17beta-hydroxysteroid dehydrogenase enzyme that converts androstenedione to testosterone . ADD is one of the most orally active pro-hormones, and displays a level of oral bioavailability far superior to any other compound. To optimize anabolic surveillance strategies, ADD and BOL were administered to veal calves, at a similar dosage and the same ratio present in ‘ready to use’ cocktails; their disposition in plasma and their elimination rate in urine were followed for 24 h. Analysis Urinary concentrations of b-BOL, a-BOL and ADD were determined (before and after deconjugation with Helix pomatia extracts) using a validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) method. To measure plasma concentrations, the same method with slight modifications was adopted. ADD was not detectable in any of the urine or plasma samples at any time.For both 17 a- and 17b-BOL the highest concentrations were detected in the first plasma samples (15 min after administration), their concentrations then decreased at similar rates and both were undetectable within 4 h after administration. In urine samples collected within 4 h after administration, concentrations of a-BOL were considerably higher than those of b-BOL, and 36 h after administration a-BOL was the only detectable metabolite. b-BOL was detectable over a period of 24 h only. The absence of ADD confirmed its double identity, i.e. not only as a metabolite but also a precursor of b-BOL, as already shown in vitro after incubation of ADD or b-BOL with calf liver microsomes . The in vivo results confirm that both ADD and b-BOL were promptly absorbed when administered to veal calves before feeding, and that their disappearance from plasma was even more rapid. About 3 h after administration a significant quantity of a-BOL was recovered in urine, while b-BOL attained concentrations only slightly higher than the EU action limit. Surprisingly, after 9 h a-BOL concentrations were already less than 2% of those detected at the previous sampling time and b-BOL concentrations were closed to the limit of quantitation. One day after treatment only a-BOL gave a feeble indication of the ‘illegal’ treatment. These findings indicate that sampling time is crucial when urine samples are collected from farmed calves for surveillance purposes.

Oral administration of boldenone and boldione to veal calves: disposition and elimination rate of boldenone metabolites

MERLANTI, ROBERTA;DE LIGUORO, MARCO;GALLINA, GUGLIELMO;MONTESISSA, CLARA
2006

Abstract

INTRODUCTION Boldenone (1,4-androstadiene-3–one, 17-ol) (BOL) and boldione (1, 4-androstadiene-3,17-dione) (ADD) are chemical derivatives of testosterone, known as strong anabolics and low to moderate androgenic agents. ADD, the dione form of BOL, is a direct precursor of that anabolic steroid, and it is activated by the same widely distributed 17beta-hydroxysteroid dehydrogenase enzyme that converts androstenedione to testosterone . ADD is one of the most orally active pro-hormones, and displays a level of oral bioavailability far superior to any other compound. To optimize anabolic surveillance strategies, ADD and BOL were administered to veal calves, at a similar dosage and the same ratio present in ‘ready to use’ cocktails; their disposition in plasma and their elimination rate in urine were followed for 24 h. Analysis Urinary concentrations of b-BOL, a-BOL and ADD were determined (before and after deconjugation with Helix pomatia extracts) using a validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) method. To measure plasma concentrations, the same method with slight modifications was adopted. ADD was not detectable in any of the urine or plasma samples at any time.For both 17 a- and 17b-BOL the highest concentrations were detected in the first plasma samples (15 min after administration), their concentrations then decreased at similar rates and both were undetectable within 4 h after administration. In urine samples collected within 4 h after administration, concentrations of a-BOL were considerably higher than those of b-BOL, and 36 h after administration a-BOL was the only detectable metabolite. b-BOL was detectable over a period of 24 h only. The absence of ADD confirmed its double identity, i.e. not only as a metabolite but also a precursor of b-BOL, as already shown in vitro after incubation of ADD or b-BOL with calf liver microsomes . The in vivo results confirm that both ADD and b-BOL were promptly absorbed when administered to veal calves before feeding, and that their disappearance from plasma was even more rapid. About 3 h after administration a significant quantity of a-BOL was recovered in urine, while b-BOL attained concentrations only slightly higher than the EU action limit. Surprisingly, after 9 h a-BOL concentrations were already less than 2% of those detected at the previous sampling time and b-BOL concentrations were closed to the limit of quantitation. One day after treatment only a-BOL gave a feeble indication of the ‘illegal’ treatment. These findings indicate that sampling time is crucial when urine samples are collected from farmed calves for surveillance purposes.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2476201
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