title: Increased immunoreactive 11-ketotestosterone concentrations in sheep feces after acth challenge.
abstract: 11-Oxoetiocholanolone and related substances are important metabolites of cortisol and are excreted via feces in ruminants. To investigate whether 11-ketotestosterone (11-KT) or its immunoreactive metabolites are formed and excreted in ruminant feces, an enzyme immunoassay (EIA) was developed and validated. The antibody was raised in rabbits against 11-KT-3-CMO:bovine serum albumin with biotinylated 11-KT as a label. The assay showed a sensitivity of 0.3 pg/well. To validate the assay biologically, 6 rams were injected with a synthetic analogue of the adrenocorticotropic hormone (Synacthen, 2 µg/kg body wt). An aliquot was collected of each fecal portion spontaneously defecated 8 h before Synacthen injection to 24 h after injection and stored at -20 °C until analysis. Samples (0.5 g) were extracted using 80% methanol and immunoreactive metabolites measured using the 11-KT EIA and an already established 11,17-dioxoandrostane (11,17-DOA) EIA. High-performance liquid chromatography separation revealed no peak in the same elution position as authentic 11-KT; therefore, reacting substances were referred to as 11-KT equivalents. In the case of 11-KT immunoreactive substances, the values increased from baseline (median, 136 ng/g feces) to a peak concentration (median, 424 ng/g) 10 to 14 h after Synacthen injection and declined afterwards. Concentrations of 11,17-DOA showed the same pattern, but the values were 2 to 4 times higher. From this data, the authors conclude that 11-KT-like substances, specifically C19 O3 -androgens with a 17ß-hydroxy group, were present in the feces. These substances originate from the adrenals and are most likely cortisol metabolites.
authors: Department of Biomedical Sciences, Institute of Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria.
authors: Omer
authors: O
authors: Sid-Ahmed
authors: Nino
authors: N
authors: Arias
authors: Rupert
authors: R
authors: Palme
authors: Erich
authors: E
authors: Möstl
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage / Q000378:metabolism; D000818:Animals; D004785:Environmental Pollutants / Q000378:metabolism*; D005243:Feces / Q000737:chemistry*; D005938:Glucocorticoids / Q000032:analysis; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism; D007124:Immunoenzyme Techniques; D011817:Rabbits; D018570:Risk Assessment; D012756:Sheep / Q000378:metabolism / Q000502:physiology*; D013739:Testosterone / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism
chemical_list: D004785:Environmental Pollutants; D005938:Glucocorticoids; D013739:Testosterone; D000324:Adrenocorticotropic Hormone; C003600:11-ketotestosterone; D006854:Hydrocortisone