Androstane im Kot von Nutztieren und ihre mögliche Bedeutung

The biological functions of androgens during gestation are not well researched yet, as androgens are often only regarded as precursors of oestrogens. Every day enormous amounts of faeces are excreted by livestock, thus faecal androgen metabolites could pose an ecological risk to sensitive organisms. The posed hypothesis that substantial amounts of androgenic substances are excreted via faeces of cows and sows was investigated through the course of this thesis. The suspected origin of those androgenic substances or their precursors is the placenta. Faecal samples were taken at the day of oestrus and 16 days later from six cows and eight sows. Furthermore, faecal samples were taken from ten cows on day 150 and eight cows on day 240 of pregnancy. Faecal samples of eight sows were collected on day 110 of pregnancy. The samples were immediately frozen after collection, later extracted, and representative androstanes were measured using four enzyme immunoassays (aetiocholanolone, epiandrosterone, testosterone, and 5β-dihydrotestosterone enzyme immunoassays). Reversed-phase high performance liquid chromatography was used to characterize the immunoreactive substances. Using an androgen receptor assay, receptor active androgenic substances were measured. In all samples immunoreactive and receptor-active androgens or their metabolites (all unconjugated) were detected. The concentration of all androstanes measured by the immunoassays and receptor active androgens increased towards the end of gestation, pointing towards a synthesis of them or their precursors in the placenta.