Progesterone effect on the biosynthesis of glycoconjugates, specifically of sulfated glycoprotein, in the endometrium of rabbit uterus.

Abstract

The endometrial scrapings obtained from the uteri of estrogen-progesterone-treated and estrogen-treated rabbits were incubated with N-acetyl-D-[1-3H]glucosamine and [35S]sulfate, and then the incubation medium (M-Fr) was separated from the tissue. The tissue was subsequently homogenized exhaustively in 0.25 M sucrose, and the insoluble residue (R-Fr) was separated. The supernatant at 8,5000 X g for 10 min of the homogenate was subjected to subcellular fractionation by discontinuous sucrose gradient ultracentrifugation, and a Golgi-rich fraction (G-Fr) was obtained. Crude glycoconjugates (glycosaminoglycans and glycoproteins) were then separated from M-Fr, R-Fr and G-Fr after pronase digestion. The amounts of the radioactivities incorporated into these glycoconjugates suggested that progesterone markedly suppressed the estrogen effect within 6 hr in R-Fr and G-Fr, whereas the suppression slightly delayed in M-Fr. The amounts of the radioactivities incorporated into acidic GC, which obtained by CPC-precipitation of the crude GC after digestion with crude heparinase, indicated that the biosynthesis of the CPC-precipitable sulfated glycoproteins was almost completely ceased by progesterone, although other glycoconjugates were still actively synthesized under the progesteronic condition.