Effect of estrogen and progesterone on the time-course of tubal ovum transport in rabbits

Effects of delayed transfer and treatment with oestrogen on the transport of microspheres by the rat oviduct

“…In addition, microspheres transferred on Day 1 and native eggs began to pass to the isthmus between 21:00 and 24:00 h of the same day and, at 03:00 h on Day 2, more than half of the eggs or microspheres were in the isthmus. This means that in the rat the ampullary-isthmic junction becomes patent to the passage of par¬ ticles nearly 18 h after ovulation and remains so for less than 12 h. This coincides with findings in the rabbit oviduct which established that the ampullary-isthmic junction becomes patent between 12 and 24 h after ovulation (Pauerstein et al, 1974) and remains open for about 16 h (Gómez & Croxatto, 1977).…”

Uterine Tube Microvascular Architecture after Oophorectomy in the Rabbit

“…Noyes et al [1959] and Pauerstein and Weinberg [1980] reported that oestradiol therapy, in rabbits castrated for 1 month, delayed ovum trans port with increased numbers of ova being retained in the oviduct. Oestradiol clearly induced 'tube locking' [Pauerstein et al, 1974] in these studies, although whether this was due to mucus or vascular changes or both is not known.…”

“…The normal delay in rabbit ovum trans port at the ampullary-isthmic junction in control animals is at least 24 h [Pauerstein et al, 1974], Jansen [1978] postulated that an increase or change in the characteristics of isthmic luminal mucus characteristics may be responsible for this observed normal delay. Verco et al [1983] proposed that the extensive subserosal venous plexus of the isthmus could, on distention (following an increase in tubal venous pressure or a reduc tion in venous smooth muscle tone), act as a sphincter around the tube: normal ovum delay at the ampullary-isthmic junction according to this proposal would thus be caused by a vascular mechanism.…”

Microvascular Architecture of the Pregnant Rabbit Oviduct

“…The relationship between ovarian or placental hormones and tubal microvasculature implied by this study, and by investigation of tubal MVA after oophorectomy [Verco et al, in press], is of particular interest when considering the proposal that variations of isthmic subserosal venous pressure or tone may be relevant in tubal transport [Verco et al, 1983a]. It was suggested that a rise in isthmic subserosal venous pressure or fall in isthmic subserosal venous tone would be associated with isthmic occlusion [Verco et al, 1983a] and could thus account for the observed delay in tubal ovum transport at the ampullary-isthmic junction [Pauerstein et al. 1974].…”