Radiolabelled uterine proteins during early pregnancy and pseudopregnancy in mice after unilateral ovariectomy and superovulation.

Uterine secretions were analysed after labelling in vivo with 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.