35SO4 administered intraperitoneally was specifically incorporated into a glycopeptide component separated by electrophoresis of the glycosaminoglycan fraction prepared from the uterine epithelia (luminal), as well as the uterine fluid of ovariectomized rats treated with estradiol-17 beta, in contrast to the rats without estrogen treatment. 2. The epithelial cells of uteri isolated from estrogen-treated ovariectomized rats incorporated 35SO4 in vitro into at least two macromolecular components. The larger molecular weight component (sodium dodecyl sulfate polyacryl-amide gel electrophoresis and/or gel filtration) labelled with 35S was observed in both the cytosol and particulate fractions, whereas the smaller molecular weight component labelled with 35S was found only in the particulate fraction. 35SO4 was also incorporated into two macromolecular components in the incubation medium, similarly to the particulate fraction. A 35 SO4-labelled glycopeptide similar to that from the epithelial particulate fraction and the incubation medium, and not from the epithelial cytosol fraction. 3. Progesterone, in contrast to estrogen, did not stimulate the sulfated blycoprotein synthesis. Moreover, progesterone administered together with or after estrogen-administration completely arrested the estrogen-dependent synthesis and secretion of the sulfated glycoproteins in the uterine epithelia.
