Abstract
Two pregnancy-associated proteins in the serum of pregnant rabbits were detected and analyzed by immunochemical methods. The newly discovered proteins are named pregnancy-associated leporine serum proteins (PALP), which consist of two subfractions. The minor fractions, PALP-1, appears specifically in association with pregnancy, and the major fraction, PALP-2, increases its concentration with progress of pregnancy. The concentration of maternal serum PALP-2 started to increase gradually at the middle stage (Day 15) of gestation and continued to increase at a significantly high rate during the period of Days 20-25, reaching the maximum level at the end of gestation. A considerably high PALP-2 level was maintained for about 15 days post partum.
