Protopine alkaloids in horse urine.

Protopine was extracted from Fumaria officinalis and purified by column chromatography. Urine samples were collected from horses and a human volunteer that had been administered either F. officinalis or protopine free base. Plant and urine samples were acetylated and analysed by GCMS after solid-phase extraction (SPE). The urinary metabolites of protopine were identified as 4,6,7,13-tetrahydro-9,10-dihydroxy-5-methyl-benzo[e]-l,3-benzodioxolo [4,5-1][2] benzazecin-12(5H)-one, 4,6,7,13-tetrahydro-10-hydroxy-9-methoxy-5-methyl-benzo[e]-1,3-benzodioxolo[4,5-1][2] benzazecin-12(5H)-one and 4,6,7,13-tetrahydro-9-hydroxy-10-methoxy-5-methyl-benzo[e]-1,3-benzodioxolo[4,5-l][2] benzazecin-12(5H)-one, chelianthifoline, isochelianthifoline and 2-O-desmethylchelianthifoline. The metabolic formation of the tetrahydroprotoberberines by closure of the bridge across N5 and C13 is rate limited and protopine-like metabolites accumulate only when the route is overloaded. Metabolism was qualitatively similar in the horse and human.

3-Methoxytyramine as an indicator of dopaminergic manipulation in the equine athlete.

The influence of sampling variables on the concentration of the dopamine metabolites 3-methoxytyramine (3MT), dihydroxyphenylacetic acid (DOPAC) and homovanilic acid (HVA) was examined in equine urine. A logarithmic transformation of the data for all horses gave distribution which approximated the normal distributions for each metabolite. The mean urinary concentration of 3 MT in horses was 214 ng/mL and the application of a threshold with a probability of 1 in 10,000 gave an actionable level of 4 microg/mL. Environmental variables were not forensically significant in determining the population distribution. HVA was not found to be a reliable indicator of dopamine or levodopa administration.