Abortifacient effects of a unique class of vasoactive lipids from Pinus ponderosa needles

Pinus ponderosa needle (PN) ingestion by late pregnant cows results in decr eased uterine blood flow, premature parturition, and retained placentae. Fu rther, plasma from PN-fed cows increases caruncular arterial tone induces p rolonged contraction) in an isolated perfused bovine placentome. A novel cl ass of vasoactive lipids was isolated and identified using a bovine placent ome assay-guided fractionation of CH2Cl2 extracts of PN. Placentome perfusi on tests indicated that 1-12-dodecanedioyl-dimyristate (14-12-14) was the m ost potent of the PN lipids for increasing caruncular arterial tone. Late p regnant guinea pigs (GP) were used to evaluate the abortifacient activity o f these vasoactive lipids. In Study 1, on d 50 of gestation, part of the co ntrol diet was replaced with chopped PN (Diet A) or chopped PN subjected to sequential extraction with diethyl ether (Et2O; Diet B); Et2O and CH2Cl2 ( Diet C); and Et2O, CH2Cl2, and methanol (Diet D). The GP on Diets A and B e xhibited shorter (P < .01) gestation lengths and reduced (P < .01) pig birt h weights than GP on the control diet or Diets C and D. Further, only GP on Diets A and B exhibited retained placentae. In Study 2, on d 50 of gestati on, part of the control diet was replaced with chopped PN that had been sub jected to exhaustive CH2Cl2 extraction and then infiltrated with either CH2 Cl2 alone (Diet E), CH2Cl2 containing 14-12-14 (Diet F or CH2Cl2 containing isocupressic acid (Diet G); then solvents were evaporated. The GP consumin g Diet F had shorter(P < .05) gestation lengths and reduced (P < .05) pig b irth weights than did GP consuming Diets E or G. The GP consuming Diet F al so exhibited a high incidence of retained placentae. These data provide evi dence that a unique class of vasoactive lipids in PN exhibit abortifacient activity in guinea pigs.