Induction of ovalbumin mRNA sequences by estrogen and progesterone in chick oviduct as measured by hybridization to complementary DNA.

A complementary DNA synthesized from ovalbumin mRNA was used in hybridization experiments to study the early effect of estrogen and progesterone on the accumulation of ovalbumin mRNA sequences in the chick oviduct. Chicks treated with estrogen withdrawn from the hormone maintain a steady level of 60 molecules of ovalbumin mRNA per tubular gland cell, at least 80% of which are localized in the cytoplasm. After estrogen administration, there is a 3- to 4-hour lag before a rapid increase in the number of ovalbumin mRNA sequences and a parallel increase in ovalbumin synthesis. Progesterone causes a more rapid increase in both ovalbumin mRNA sequences and ovalbumin synthesis with a lag period of only 90 min. The hybridization results demonstrate that both estrogen and pregesterone affect the amount of ovalbumin mRNA per cell. The 3-hour lag period seen with estrogen appears to be caused by some event after the binding of the estrogen receptor to chromatin but prior to change in the rate of transcription of the ovalbumin gene.