Steroid hormones differentially induce transcription of the chicken ovalbumin gene, but stabilize the mRNA with the same half-life.

The stabilization of chicken ovalbumin (OVA) mRNA by different classes of steroid hormones (estrogen, progesterone, glucocorticoid, and androgen) was studied in the oviducts of chicks treated with combinations of four steroids. The combination of estrogen with progesterone, glucocorticoid, or androgen enhanced the induction of the OVA gene more than did estrogen alone. Run-on analysis of the isolated oviduct nuclei to measure the transcription rate of the OVA gene showed that the enhanced induction of the OVA gene by the combined hormone treatments was partly caused by an increased rate of transcription. The half-life of OVA mRNA as determined using a transcription inhibitor (actinomycin D) was estimated to be about 24 h irrespective of the hormone treatment, though the half-life was about 6 h in the absence of hormones. These results suggested that the prolongation of the half-life of OVA mRNA by steroid hormones is constant irrespective of differential transcription rates of the OVA gene.