A question that comes to my mind after reading the recent messages
concerning the comparison of circulating progesterone in animals evaluated
in different labs is what influence the assay system may have upon these
comparisons.  My intension is not to critisize any particular assay. 
However, the possibility exsitst that different assays systems may result
in different findings. 

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Andrew J. Roberts
USDA-ARS
U.S. Meat Animal Research Center
P. O. Box 166
Clay Center, Nebraska  68933-0166
Phone 402-762-4186
Fax 402-762-4382
Email roberts@email.marc.usda.gov
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