Steroid receptors in rat uteri: postmortem retention of specific binding functions in crude tissue preparations

Steroid receptor measurement by steroid binding analysis is a clinically useful procedure. The determination of steroid binding by specific receptors is thought to reflect the biological status of the test specimen and thereby aid prediction of patient response to endocrine therapy. The need for rapid excision of a specimen and transfer to a cold environment is believed necessary to allow reliable receptor evaluation. The optimal method of processing specimens for receptor assays, however, remains to be determined. This article reports our results on the hormone specific binding functions of rat uterine estrogen and progesterone receptors in relation to their time postmortem in situ. Steroid binding by inactive (cytoplasmic) and activated (nuclear) receptors and the processes of receptor transformation, translocation and nuclear association have been studied. Contrary to generally held notions, our results indicate that the binding functions were not altered up to 1.5 hours postmortem in situ relative to their behavior in incubation media at 2 degrees C. Thus, this apparent stability of the steroid receptors, in situ, allows greater freedom in the procurement of tissues for receptor analyses in clinical and basic research studies.