Absorption of 3-nitropropanol (miserotoxin aglycone) from the compound stomach of cattle.

Miserotoxin, the toxic component of certain Astragalus spp. (Leguminosae), was rapidly hydrolyzed to 3-nitropropanol (NPOH) in the rumen of cattle dosed with timber milkvetch (A. miser var. serotinus). The aglycone showed a rapid rate of disappearance from the rumen with an average half-life of 1.24 h. In contrast to the passage of Co-EDTA, which showed an exponential rate of increase in the abomasum, NPOH was not detected in abomasal fluid collected from dosed cattle. Rapid absorption of NPOH from the rumen was shown by plasma levels of 3-nitropropionic acid (NPA) and inorganic nitrite, but conversion of NPOH to NPA was not observed to any significant extent in the rumen.