Uterine fluid and the duration of pseudo-pregnancy following transection of the uterus in the rat.

Abstract

When the posterior ends of the uterine horns in cycling female Hooded Wistar rats were transected, fluid accumulated in the uterine lumen. During pseudopregnancy, the mean volume of uterine fluid in these rats fell from 0\m=.\97\m=+-\0\m=.\18ml on Day 2 to 0\m=.\06\m=+-\0\m=.\07ml on Day 8 (P< 0\m=.\001).The volume remained low until the next onset of pro-oestrus. Uterine fluid in normal rats at the time of oestrus contained 41\m=.\63\m=+- 3\m=.\99mequiv./1 potassium, a higher level than that in blood plasma, and 2\m=.\07\m=+-\0\m=.\88mg/ml total protein. Following transection of the uterine horns, the level of potassium remained high. The mean total protein concentration rose to three to thirteen times the normal value. Transection of the uterine horns led to an increase in the mean duration of pseudopregnancy from 13\m=.\4\m=+-\0\m=.\20days to 15\m=.\2\m=+-\0\m=.\33days (P<0\m=.\001).When uterine fluid was withdrawn from transected horns during pseudopregnancy, the duration of pseudopregnancy was reduced to 14\m=.\3\m=+-\0\m=.\29days (P<0\m=.\05).It is concluded that retention of uterine secretion is a causal factor in the prolongation of pseudopregnancy resulting from uterine transection.