DIFFERENTIAL C-JUN GENE-EXPRESSION WITH TONICALLY ADMINISTERED STEROIDS IN RAT OVARY AND UTERUS

OBJECTIVE: The purpose of this study was to evaluate the induction of the early regulatory gene c-jun in response to tonic exposure to estra diol and progesterone in rat ovary, uterus, and adrenal tissues. STUDY DESIGN: Pellets containing estradiol-17 beta, progesterone, and estra diol-17 beta plus progesterone were placed subcutaneously in immature female Sprague-Dawley rats (N = 24). The ovary, uterus, and the adrena l were evaluated for c-jun expression by Northern analysis at 24 and 4 8 hours. RESULTS: The c-jun messenger ribonucleic acid expression in t he ovary and adrenal gland was inhibited with high, nonphysiologic dos es of estradiol in progesterone and was induced with physiologic level s of estradiol. Physiologic levels of progesterone do not appear to in fluence the expression of c-jun in the ovary or adrenal gland. Uterine c-jun expression to estradiol and progesterone is generally the oppos ite of that observed in the ovary. CONCLUSION: These findings suggest that there is both tissue and dose specificity of c-jun gene expressio n in steroidogenic and steroid-responsive tissues when steroid hormone s are tonically administered.