Effect of Estradiol Dipropionate on Protein Synthesis in Oocytes and Ovary of the Sea Urchin Strongylocentrotus intermedius at Different Stages of the Reproductive Cycle

We studied protein synthesis in the oocytes and ovary of the sea urchin Strongylocentrotus intermedius at different stages of the reproductive cycle after treatment with estradiol dipropionate. During the early development of oocytes and active gametogenesis, this estrogen induced the incorporation of ³H-leucine in the oocytes. The changes in synthetic activity of cells were accompanied by an elevated efficient incorporation of free amino acid in proteins due to its increased pool, increased tissue permeability for precursors, and increased rate of protein synthesis. Before spawning, estradiol dipropionate did not cause any changes in protein synthesis. After estradiol dipropionate treatment, the inhibitors of protein synthesis, puromycin and actinomycin D, decreased the intensity of ³H-leucine incorporation in the oocytes and protein synthesis in the ovary. The involvement of estradiol dipropionate in the regulation of protein synthesis in the sea urchin gonad is discussed.