Search

Summary.Uterine secretions were analysed after labelling with l-[4,5-3H]leucine. During pro-oestrus major protein peaks were seen with approximate mol. wt 2·0 × 104, 2·7 × 104, 4·0 × 104, 5·7 × 104, 7·8 × 104and 13·0 × 104. Qualitative changes were observed during the first 4 days of pregnancy. On day 4 p.c. secretions revealed two prominent peaks with mol. wt 6·7 × 104and 12·5 × 104, four peaks between 2·0 and 4·7 × 104and one at 8·5 × 104and one at 20·0 × 104. Profiles similar to those on Day 4 p.c., and implantation, were induced in ovariectomized females by administration of exogenous progesterone and oestradiol, whereas the proteins detected after administration of exogenous oestradiol alone were essentially similar to those found at pro-oestrus. Ovariectomized mice treated with the steroid sequence to mimic Day 4 p.c. profiles but not given the final injection of oestradiol showed no detectable labelled proteins. Injection of progesterone or oestradiol alone, in the final sequence of injections given to ovariectomized pregnant females treated with progesterone, did not induce blastocyst implantation. These studies indicate a synergistic relationship between progesterone and oestrogen in the secretion of uterine macromolecules.

Summary.Uterine secretions were analysed after labelling in vivowith l-[4,5-3H]leucine. The acid-precipitable counts were highest on Day 1 p.c., low on Day 2, lowest on Day 3, and similar to Day 2 values on Day 4 p.c.After unilateral ovariectomy the acid-precipitable counts for the horn ((+)ovary) ipsilateral to the remaining ovary were higher than those in the contralateral horn ((–)ovary) for each condition studied. Superovulation yielded slightly higher acid-precipitable counts in the (–)ovary and (+)ovary horns of pregnant mice on Day 3 p.c., and in the (+)ovary horn only for pseudopregnant mice on Day 2 p.c.The Day 2 counts for the (+)ovary and (–)ovary horns of the superovulating pseudopregnant mice were higher counts than those for superovulating pregnant mice, but the reverse occurred for (+)ovary horns only on Day 4 p.c.No qualitative differences between pseudopregnant and pregnant mice were observed on Day 4 and superovulation appeared to enhance the profiles obtained.

Summary.Mouse blastocysts were incubated in microdrop cultures in the presence of D-[6-3H]glucosamine. The embryos and the incubation medium were analysed for the incorporation of label into acid-precipitable material. Of the precursor incorporated into blastocysts, 8–13% was detected in the medium. Several glycoproteins were found in the blastocysts and one of molecular weight about 87 000 was also detected in the extracellular medium. In the presence of tunicamycin, the amount of the labelled glycoprotein was reduced by 30–40% in the embryos and 47–69% in the medium. However, the same relative proportion of label was still detected in the extracellular fraction of 87 000 mol. wt. The study demonstrates the synthesis and release of a glycoprotein by mouse blastocysts, the mechanism of which is tunicamycin-insensitive.