ISOLATION OF A BOVINE UTEROTROPIC PLACENTAL FACTOR AND DEVELOPMENT OFAN ENZYME-IMMUNOASSAY IN PERIPHERAL SERUM

Bovine uterotropic placental factor (bUTPF) was obtained from bovine t erm placentae that had been homogenized and extracted in acidic medium . The extracts were chromatographed on Sephadex G-75, a fraction named native bUTPF was obtained, and an antiserum was generated. The native bUTPF was chromatographed on Sephacryl S-300 HR, and a 230-kDa fracti on was obtained. A competitive enzyme immunoassay (EIA) was developed to determine bUTPF levels during gestation. This EIA was linear betwee n 0 and 80 mu g/ml (with a detection limit of 0.2 mu g/ml) and showed intraassay and interassay coefficients of variation of 11.2% and 15.5% , respectively. Bovine UTPF serum levels during gestation were determi ned by means of a cross-sectional study between the first month of ges tation and delivery Maximal serum levels of bUTPF were found during th e first month of gestation: 7.1 +/- 1.9 mu g/ml (p < 0.05). In another cross-sectional study, blood samples were collected from 105 cows bet ween 8 and 25 days postinsemination (day of insemination = Day 0). Lev els of bUTPF were found to be significantly higher (p < 0.05) by Day 1 7 compared to Day 0 (5.8 +/- 2.2 mu g/ml vs. 1.2 +/- 0.7 mu g/ml). We conclude that bUTPF is detected by EIA in maternal peripheral serum ea rly during gestation in the bovine species.