Techniques for detection of estrogenicity.

The purpose of this workshop was to bring together the collective experience of many disciplines to discuss and evaluate tech? niques for the detection of functional estro? genicity. Estrogenicity was first defined as a physiological response to a compound that induced estrus in vivo. The bioassay for induction of estrus developed into a uterotropic assay. The classical tissue response evaluated in this assay was an estrogeninduced increase in wet weight and tissue mass. Tissue response follows a time course of stimulation, including an early phase at 2 to 4 hr, followed by a second later phase. A higher dose of compound generates a stronger response. Weak estrogens exhibit the early response phase, but then the response fails off; however, multiple low doses of weak estrogens mimic the full activity of strong estrogens. A host of chemical and molecular biological factors are involved in the uterotropic response.