[Estradiol stimulation of ribosomal synthesis in adenohypophysis cells]

A single dose of 10 micrograms oestradiol injected to a male rat stimulates in the anterior pituitary the synthesis of ribosomal RNA and of the associated proteins. This stimulation is shown using in vitro double-labeling of RNA with adenine or guanine and of proteins with valine. The analysis of polysomes reveals the incorporation of the neo-synthesized molecules into the 40 S and 60 S subunits. Therefore, the stimulation of ribosomal RNA and protein biosynthesis by oestradiol is a coordinated process. No change in the whole polysome distribution is observed in these conditions though such a modification may occur in a specific cell population without being detected by using sucrose gradient analysis.