Observations on the Mechanism of Prolongation of Pseudopregnancy in the Rat Following Transection of the Uterine Horns

Abstract

Summary. Transection of the uterine horns near to their cervical ends (posterior uterine section) led to a prolongation of pseudopregnancy from 13\m=.\1\m=+-\0\m=.\16 (control) to 14\m=.\9\ m=+-\ 0\m=.\24 days (P<0\m=.\001). This was significantly greater than the prolongation following transection of the uterine horns one third of the way from the uterotubal junction to the uterine bifurcation (14\m=.\0 \ m=+-\ 0\m=.\16 days, P<0\m=.\01).When unilateral ovariectomy was accompanied by contralateral posterior uterine section, the prolongation of pseudopregnancy ( 14\ m=. \ 5\ m=+-\ 0\m=.\20 days, control 12\m=.\8\ m=+-\ 0\m=.\25 days, P< 0\m=.\001) was greater than when accompanied by ipsilateral posterior uterine section (13\m=.\7 \ m=+-\ 0\m=.\20days, P<0\m=.\02).These results indicate a quantitative and a unilateral component in the effects of uterine section, and support the hypothesis that prolongation of pseudopregnancy following posterior uterine section is brought about by the same mechanism as that following hysterectomy.

Prolongation of Pseudopregnancy in the Rat by Slitting the Uterus

“…Similar results were also obtained by O'Shea (1971) when he found that merely sectioning both uterine horns in the rat while leaving uterine blood vessels intact led to a sig¬ nificant increase in the length of pseudopregnancy. It is also interesting that slitting can eliminate the systemic, but not the local, luteolytic effect in some animals.…”

Uterine Fluid and the Duration of Pseudopregnancy Following Transection of the Uterus in the Rat

“…However, uterine transection does lead to a prolongation of pseudo-58 J. D. O'Shea pregnancy (Bradbury et al, 1950;O'Shea, 1970). There is evidence to suggest that this effect on pseudopregnancy is due to an interference with the normal uterine luteolytic mechanism (O'Shea, 1971b), but …”