Some hematological and histopathological effects of the alkaloids gramine and hordenine on meadow voles (Microtus pennsylvanicus).

Meadow voles (Microtus pennsylvanicus) were used to evaluate the relative toxicity of the alkaloids, gramine and hordenine, which are present in reed canarygrass (Phalaris arundinacea) and to assess their effects on the quality of this grass as a forage. One hundred and twenty meadow voles, 31 days of age, were fed gramine (0, 0.125, 0.25, or 0.5% of a nutritionally complete diet) or hordenine sulfate (0, 0.15, 0.31, or 0.62% of the diet) for 21 days. The effects of treatment on growth, mortality, hematology, blood chemistry, and histology of body organs were examined. Approximately one-third of the voles died when fed either 0.25 or 0.50% gramine. Voles that survived on gramine diets had kidney lesions, glycosuria, higher intakes (P less than 0.05), and lower weight gains (P less than 0.01) than control animals. Voles fed 0.25 and 0.50% gramine had increased circulating reticulocyte levels (P less than 0.01) and those fed 0.125% gramine had higher alkaline phosphatase activity (P less than 0.05) than the control voles. Hordenine did not affect vole diet intake, weight gain, or rate of mortality. Voles fed hordenine developed kidney lesions and glucose was detected in the urine of 62% of these animals. Gramine was more toxic than hordenine on a molar equivalent basis.