Development of a sensitive enzymeimmunoassay (EIA) for progesterone determination in unextracted bovine plasma using the second antibody technique.
A simple direct enzymeimmunoassay (EIA) on microtiter plates for plasma progesterone using the second antibody coating technique and horseradish peroxidase (HRP) as the enzyme label (EIA-HRP) is described and compared with an identical EIA procedure which employed alkaline phosphatase (AP) as the enzyme label (EIA-AP). The assays used antiserum raised against progesterone-7-carboxyethlthioether-BSA in rabbits. Both systems were further compared with the conventional direct progesterone radioimmunoassay (RIA) in regular use. The enzymes HRP and AP were coupled to progesterone-6 beta-hydroxy-hemisuccinate by a mixed anhydride method. While the precision of EIA-HRP was comparable to RIA, the sensitivity in terms of the lowest detection limit obtained in EIA-HRP was about 10 times better than that seen in RIA. Progesterone estimates from plasma samples in EIA-HRP showed good correlation (r = 0.94) with the RIA values and the levels measured in the two systems were identical. Progesterone estimates from plasma samples in EIA-AP were at least three times higher than those obtained by either EIA-HRP or RIA. Thus, only the EIA-HRP but not the EIA-AP was suitable for the reliable direct measurement of progesterone in plasma.
Prakash
B S
BS
Insitut für Physiologie der Süddeutschen Versuchs-und Forschungsanstalt für Milchwirtschaft, Technische Universität München, F.R.G.
Meyer
H H
HH
Schallenberger
E
E
van de Wiel
D F
DF
D000818:Animals; D001241:Aspirin / Q000097:blood; D002417:Cattle; D005260:Female; D007124:Immunoenzyme Techniques; D011374:Progesterone / Q000097:blood* / Q000276:immunology
D011374:Progesterone; D001241:Aspirin