The identification of C-18 neutral steroids in normal stallion urine

As part of a continuing research program associated with the detection of anabolic steroid residues in horse urine, normal samples from entire male horses have now been investigated. Isomers of three C-18 neutral steroids; 4-estren-17-ol-3-one (1), estrane-3,17-diol (2) and an unsaturated estranediol having a possible structure (3), have been identified in urine samples from two male horses aged 8 and 14 years. Of these three steroids, compound (2) was not detected in the urine of a 2.5 yr old entire male nor in the majority of post-race urine samples from entire male horses average age 3.8 yrs (n = 34). Ten of these samples showed tentative indications of this compound. Although the isolation of isomers of estrane-3,17-diol from human non-pregnancy urine has been reported previously, analysis of non-pregnancy urine samples in the present study did not reveal the presence of these compounds.