title: Characterization of a rapid and sensitive enzyme immunoassay (EIA) for progesterone applied to conditioned cell culture media.
abstract: Progesterone accumulation in conditioned media is a frequently employed endpoint for in vitro cell culture of steroidogenic cells. Although radioimmunoassay (RIA) has been the predominant method for measurement of progesterone, a number of nonradiometric immunoassays have been described but they have not been applied to conditioned media. Here, we report the characterization of a microtitre plate enzyme immunoassay (EIA) for determination of progesterone in conditioned media. The EIA has a sensitivity of 0.3 pg per well with intraassay and interassay coefficients of variation of 7.3 and 10.2%, respectively. The specificity of the EIA is no different than that of a comparable RIA showing crossreactivities of less than 0.1% for other steroids except 5 alpha-pregnan-3,20-dione (47%) and 11 alpha-hydroxyprogesterone (18%). Progesterone levels from conditioned cell culture media of either rat or human granulosa cell cultures measured by both EIA and RIA were in close agreement (r = 0.96) and serial dilutions of culture samples in the EIA were parallel to those of the standards. Also, extraction of culture media prior to EIA was found not to be necessary. Thus, this EIA is a highly sensitive and specific assay that provides a rapid, simple, inexpensive, and non-radiometric alternative to radioimmunoassay for measurement of progesterone in conditioned cell culture media.
authors.affiliation: University of Iowa, College of Medicine, Department of Pharmacology, Iowa City 52242.
authors.forename: B G
authors.initials: BG
authors.lastname: Kasson
authors.forename: S
authors.initials: S
authors.lastname: Bai
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Tobin
authors.forename: B
authors.initials: B
authors.lastname: Kessel
mesh_terms: D000818:Animals; D003429:Cross Reactions; D017077:Culture Media, Conditioned / Q000737:chemistry*; D005260:Female; D006107:Granulosa Cells / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D011374:Progesterone / Q000032:analysis*; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D014327:Trophoblasts / Q000378:metabolism
chemical_list: D017077:Culture Media, Conditioned; D011374:Progesterone