Effects of progesterone on the synthesis of ribonucleic acids in the uterus

Abstract

The effects of progesterone stimulation on the synthesis of different species of RNA in the uterus were studied. Rates of synthesis of total RNA, rRNA and tRNA were determined at 48 h after the first of two daily injections of 6.7 ng of 17β-estradiol plus 0.33 mg of progesterone. Control mice received equivalent injections of 6.7 ng of 17β-estradiol only. The rate of synthesis of total RNA was 1.47 (nmoles of UMP incorporated into RNA/min per uterus) in control uteri, and increased to 3.10 in uteri stimulated by progesterone. Rates of synthesis of rRNA and tRNA were only about 0.6–1.3% of those for total RNA. The rate for 28-S rRNA increased from 12.8 (pmoles of UMP/min per uterus) in control mice to 24.3 in mice which received progesterone, and for tRNA synthesis from 12.3 (pmoles of UMP/min per uterus) in control uteri to only 17.6 in progesterone-stimulated uteri. It was concluded that progesterone treatment caused increases in the synthesis of all classes of uterine RNA, and did not preferentially stimulate the synthesis of rRNA or tRNA.