RADIOIMMUNOASSAY OF SALIVA ESTRONE SULFATE IN PREGNANT SOWS

The aim of this study was to establish radioimmunoassay (RIA) for sali va estrone sulfate (E1S), and to elucidate changes in saliva E1S durin g pregnancy in the sow. Saliva E1S was extracted using a commercially available solid phase column, and the E1S fraction obtained was subjec ted to RIA. The sensitivity of the RIA was 29.7 pg/tube. The intra-and inter-assay coefficients of variation were 5.5-8.4% and 13.1-19.5%, r espectively. Mean recovery for E1S added to saliva samples was as high as 99.9%. A significant positive correlation (r=0.54, n=69, p<0.01) e xisted between saliva and plasma E1S concentrations. During gestation, the changing patterns of saliva and plasma E1S concentrations were es sentially the same, and two peaks of E1S concentrations were observed, one around day 30 and another just before parturition, although E1S c oncentrations in saliva remained at only 2.4-38.1% (mean 11.4%) of tho se in plasma E1S. Thus, the present study has made it possible to meas ure saliva concentrations of E1S and demonstrated a high degree of pos itive correlation between saliva and plasma E1S concentrations. These results suggest that diagnosis of early pregnancy and of normal or abn ormal fetal development could be made by measurements of E1S in saliva .