Radiolabelled rat uterine luminal proteins and their regulation by oestradiol and progesterone.
Radiolabelled uterine luminal proteins were obtained 6 h after instillation of 5--10 muCi [35S]methionine into the lumen of each uterine horn of rats. The proteins were analysed electrophoretically on 6% polyacrylamide gels and incorporation of the precursor into the separated proteins was estimated in 0-18 cm gel slices by scintillation spectrometry. Major incorporation was obtained on Day 5 of pregnancy in a group of proteins of approximate mol. wt 3 X 10(4), 4-5 X 10(4) and 5-5 X 10(4) and in proteins of mol. wt 8--10 X 10(4). During pro-oestrus, substantial incorporation of the precursor occurred in a group of protein of mol, wt 13-5 X 10(4), 12-5 X 10(4) and 7-5--8-0 X 10(4) and slight incorporation in proteins of mol. wt 4-5 X 10(4). These changes were mimicked in ovariectomized females by injections of appropriate steroids: progesterone and oestradiol were necessary to induce the proteins detected during pregnancy, oestradiol alone was able to reproduce the changes observed at pro-oestrus. The proteins in the lumen appear to be of uterine origin because radiolabelled serum proteins were not detected in the lumen after an i.p. injection of the isotope. Also, labelled proteins were detected in the horn receiving the isotope but not in the contralateral horn injected with saline. Cycloheximide, given i.p. simultaneously with the isotope but not in the contralateral horn injected with saline. Cycloheximide, given i.p. simultaneously with the isotope, suppressed synthesis of uterine proteins.
D000818:Animals; D002369:Castration; D003513:Cycloheximide / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D005260:Female; D008715:Methionine / Q000378:metabolism; D011247:Pregnancy; D011359:Proestrus; D011374:Progesterone / Q000494:pharmacology*; D014176:Protein Biosynthesis; D051381:Rats; D014599:Uterus / Q000187:drug effects / Q000378:metabolism*
D011374:Progesterone; D004958:Estradiol; D003513:Cycloheximide; D008715:Methionine