Deoxyribonucleic acid and ribonucleic acid synthesis during phosvitin induction by 17beta-estradiol in immature chicks.

1. During the first 48 hours following estrogenization a total increase in liver weight, DNA, RNA, and liver protein is observed. 2. Inhibition of DNA synthesis with 300 mg of hydroxyurea/l00 g body weight (injected every 12 hours) does not impair the primary or secondary stimulation of phosvitin synthesis. 3. The early kinetics of the primary and secondary stimulation of phosvitin synthesis by estradiol are characterized by a lag of 12 and 6 hours, respectively. I f during these lag phases RNA synthesis is blocked by a-amanitin (0.02 mg per kg body weight, injected twice in 12 hours interval), no further synthesis of phosvitin is observed. 4. Total polysomal mRNA synthesis doubles during the oc-amanitin-sensitive period after the primary and secondary stimulation. During that same period, but after the secondary stimulation only, rRNA synthesis increases by about 90%.