Submitted to: Veterinary and Human Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 1999
Publication Date: January 20, 2000
Citation: SCHOCH, T.K., GARDNER, D.R., STEGELMEIER, B.L. GC/MS/MS DETECTION OF PYRROLIC METABOLITES IN ANIMALS POISONED WITH THE PYRROLIZIDINE ALKALOID RIDDELLINE. VETERINARY AND HUMAN TOXICOLOGY. 2000. Interpretive Summary: Plants containing pyrrolizidine alkaloids cause poisoning in livestock and occasionally people. Diagnoses of pyrrolizidine alkaloid poisonings are not easy as the lesions are non-specific and are difficult to distinguish from other hepatic diseases. However, the toxic metabolites of the pyrrolizidine alkaloid remain in the blood and liver and can be detected using chemical aand spectroscopic methods. This paper describes the use of a gas chromatograph/tandem mass spectrometer to detect the pyrrolizidine alkaloid metabolites in liver and blood samples. Calibration of the method was attempted by synthesis of standards to model the metabolite-tissue conjugates. The method was applied to samples taken from pigs poisoned with the pyrrolizidine alkaloid riddelliine from Senecio riddellii. Toxic metabolites were detected in both liver and blood samples at levels between n2 and 64 ppm; however, the levels of detected metabolites did not correlat to the degree of poisoning in the animals.
Technical Abstract: Pyrrolic metabolites from pyrrolizidine alkaloids (PAs) were detected in liver and dried blood samples using a gas chromatography/tandem mass spectrometry (GC/MS/MS) selected product-ion monitoring method. A calibration curve was constructed using a protein-metabolite conjugate spiked into dried bovine blood. These spiked samples served as a model for rtissues from animals poisoned by the toxic metabolite of PAs. Tissue samples from pigs fed various amounts of the PA alkaloid riddelliine (from Senecio riddellii) were analyzed for pyrrolic metabolites, and the results were applied to the calibration curve to provide a measure of the degree of PA poisoning. Pyrrolic metabolites were detected in liver and blood samples of all poisoned animals at levels between 2 and 64 ppm. Although differences in metabolite levels could be discerned under the reported experimental conditions, the amount detected did not correlate with the dose of riddelliine given; and livers fixed with formalin gave greatly reduced recovery than those same livers either frozen or freeze dried.