Toxic Extracts in Ponderosa Pine Needles that Produce Abortion in Mice

Abstract

A reliable method to measure presence and quantity of the toxic factor in needles of ponderosa pine (Pinus ponderosa Laws.) was developed using embryo implantation and gestation in laboratory mice as the basis of the assay. The abortiofacient factor was present in both aqueous and acetone extracts of ponderosa pine needles. Control animals had significantly (P<0.1) greater number of viable embryos at 124, 148, and 172 hr post-coitum than mice fed pine needle extracts. A gestation study verified results from the implantation experiment, as few mice fed pine needle extracts delivered normal litters. Frequently, mice receiving the concentrated aqueous extract had diarrhea and decreased feed intake. Failure of implantation by 124 hr postcoitum in bred mice fed aqueous or acetone extracts of ponderosa pine can be used as an index of the risk involved in grazing ponderosa pine ranges, but cannot be used to predict losses.