Oxytocin Induces Prostaglandin F2α Release in Pregnant Cows: Influence of Gestational Age and Oxytocin Receptor Concentrations1

Fuchs, Anna‐Riitta; Rollyson, M K; Meyer, Michael D.; Fields, Michael J.; Minix, J M; Randel, R. D.

doi:10.1095/biolreprod54.3.647

Cited by 45 publications

(30 citation statements)

References 38 publications

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“…During most of pregnancy, the uterus will respond to oxytocin with PGF pulses (Schallenberger et al, 1989;Fuchs et al, 1996) but still luteolysis does not occur. For us, the two most logical responses to this physiological question are: 1) There is a substance protecting the CL from PGF action during much of pregnancy or 2) PGF does not reach the CL during most of pregnancy, perhaps due to lack of PGF transport via the normal local transport pathways.…”

Section: Discussionmentioning

confidence: 99%

“…First, it seems likely that the contralateral CL regresses due to PGF secretion from the contralateral uterine horn, since CL do not undergo spontaneous regression in ruminants with the uterus removed (Wiltbank and Casida, 1956;Mapletoft et al, 1976b). Related to this idea, responsiveness to oxytocin and the ability of the uterus to synthesize and secrete PGF persists throughout pregnancy with increases in concentrations of PGFM of approximately 6-fold when oxytocin is administered to cows between day 50 and 280 of pregnancy (Schallenberger et al, 1989;Fuchs et al, 1996). Second, the uterine horns were not isolated in our experiment and therefore whatever local agent is involved in this process must have a difference in action on the ipsilateral than the contralateral ovary.…”

Section: Period III Prevention Of Later Luteolysis During Pregnancy mentioning

confidence: 99%

See 1 more Smart Citation

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Wiltbank¹,

Meidan²,

Ochoa³

et al. 2016

Anim Reprod

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In ruminants, there are specific times during the estrous cycle or pregnancy when the corpus luteum (CL) may undergo regression. This review has attempted to summarize the physiological and cellular mechanisms involved in CL regression or maintenance during four distinct periods. The first period is near day 7 when animals that are ovulating after a period of low circulating progesterone (P4), such as first pubertal ovulation or first postpartum ovulation, are at risk of having a premature increase in Prostaglandin F2α (PGF) secreted from the uterus resulting in early CL regression and a short estrous cycle. The second period is when normal luteolysis occurs at day 18-25 of the cycle or when the CL is rescued by interferon-tau secreted by the elongating embryo. The uterine mechanisms that determine the timing of this luteolysis or the prevention of luteolysis have been generally defined. Induction and activation of endometrial E2 receptors result in induction of endometrial oxytocin receptors that can now be activated by normal pulses of oxytocin. Of particular importance is the observation that the primary mechanisms are only activated through local (ipsilateral) and not a systemic route due to transfer of PGF from the uterine vein to the ovarian artery. In addition at the CL level, studies are providing definition to the cellular and molecular mechanisms that are activated in response to uterine PGF pulses or pregnancy. The third period that is discussed occurs in the second month of pregnancy (day 28-60) when undefined mechanisms result in CL maintenance of an ipsilateral CL but regression of a contralateral (opposite side from pregnancy) CL. The final period that is discussed is regression of the CL just prior to parturition. Although, cortisol from the fetus appears to be the primary initiator of luteolysis, PGF seems to be the final signal that causes regression of the CL. Thus, in all four periods, regression of the CL is likely to be caused by the direct actions of PGF that is secreted from the uterus. The uterine mechanisms that result in secretion of PGF seem to be normally inhibited during the early luteal phase, making short luteal phases not a normal event, and are altered during early pregnancy (day 18-25) resulting in prevention of luteolysis. During much of pregnancy, the mechanisms that cause PGF secretion from the uterus in response to oxytocin are intact but luteolysis does not normally occur, perhaps due to lack of efficient utero-ovarian transfer of PGF.

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Section: Discussionmentioning

confidence: 99%

Section: Period III Prevention Of Later Luteolysis During Pregnancy mentioning

confidence: 99%

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Wiltbank¹,

Meidan²,

Ochoa³

et al. 2016

Anim Reprod

View full text Add to dashboard Cite

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“…Uterine contractions elicited by oxytocin, at least in pregnancy, are believed to be linked with prostaglandin release (Soloff and Hinko, 1993;Fuchs et al, 1996b;Chaud et al, 1997a). Prostaglandin F 2α was shown to be increased in the myometrium of various pregnant animals near term relative to the increase of OTR (Soloff and Hinko, 1993;Fuchs et al, 1996a) and their concentration determines the magnitude of oxytocininduced prostaglandin F 2α release.…”

Section: Activity and Regulation Of Uterine Peristaltic Activitymentioning

confidence: 99%

“…The directionality of uterine peristalsis with predominantly cervicofundal waves of contraction emerging in the isthmic region of the uterus is a striking phenomenon, which may be related to the finding of a high concentration of OTR in the bovine cervical mucosa at oestrus (Fuchs et al, 1996b), thus rendering the cervix as the possible pacemaker of cervicofundal contractions. In oestrous ewes, oxytocin binding site concentrations were highest within the inner dense collagenous cervix in comparison with pregnant, ovariectomized or anoestrous animals (Matthews and Ayad, 1994).…”

Section: Activity and Regulation Of Uterine Peristaltic Activitymentioning

confidence: 99%

Uterine peristalsis during the follicular phase of the menstrual cycle: effects of oestrogen, antioestrogen and oxytocin

Kunz

Noe²,

Herbertz³

et al. 1998

Human Reproduction Update

115

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In the normal cycles, as well as during extremely elevated oestradiol concentrations and following oxytocin administration, the peristaltic contractions were always confined to the subendometrial layer of the muscular wall. The results and the review of literature indicate that uterine peristalsis during the follicular phase of the menstrual cycle is controlled by oestradiol released from the dominant follicle with the probable involvement of oxytocin, which is presumably stimulated together with its receptor within the endometrial-subendometrial unit and therefore acting in an autocrine/paracrine fashion. Since unphysiological stimulation with oestradiol and oxytocin did not significantly increase the frequency of uterine peristalsis in the late follicular phase of the cycle it is assumed that normal preovulatory frequency of uterine peristalsis is at a level which cannot be significantly surpassed due to phenomena of refractoriness of the system.

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“…Oxytocin, mediated by OTR, is able to induce the production of PGF 2 and PGE 2 in the placental tissues (Moore et al 1988, Meier et al 1995, Fuchs et al 1996. PGE 2 can stimulate vascular dilation (Armstrong et al 1995) whereas PGF 2 may promote placental growth since PGF 2 treatment increases the placentome weights at days 90-100 of pregnancy (Weems et al 1994).…”

Section: Figurementioning

confidence: 99%

Regulation of oxytocin receptor in the placentome capsule throughout pregnancy in the ewe: the possible role of oestradiol receptor, progesterone receptor and aromatase

Leung

Reynolds²,

Wathes³

1998

Journal of Endocrinology

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The hormonal regulation of uterine oxytocin receptors (OTR) during the establishment of pregnancy and at parturition has been studied extensively, but little information is available during mid-pregnancy. This study investigated the localisation of OTR mRNA in the ovine placentome throughout gestation and related this to expression patterns for the putative regulatory agents aromatase, oestradiol receptor, progesterone receptor and oxytocin. Placentomes were collected at regular intervals throughout pregnancy for in situ hybridisation analysis and immunocytochemistry (oestradiol receptor only). Results were quantified by optical density measurements of autoradiographs. Progesterone receptor mRNA was localised to the caruncular tissues on day 30 but became undetectable by day 34. Aromatase mRNA appeared in the fetal villi at days 34-40, with concentrations peaking at days 52-55 and again at days 132-137. Oestradiol receptor mRNA was localised to the caruncular tissues from days 13 to 30 and found in the maternal villi and placentome capsule from days 45 to 70. Oestradiol receptor protein was barely detectable in either tissue. OTR mRNA was localised to the placentome capsule at days 34-40, remaining high at day 45 and declining to basal levels by days 132-137. Oxytocin mRNA was not detected in the placentome. In conclusion: (1) progesterone acting via its receptor may suppress the expression of aromatase and OTR in early pregnancy; (2) the up-regulation of OTR expression in the capsule may not involve the oestradiol receptor; (3) there is a differential regulation between different regions of the uterus as the increase in the placentome capsule occurs at a time when concentrations in the rest of the endometrium and myometrium remain low; (4) oestradiol receptor expression in the placentome may be regulated at the translational level; and (5) there is no local production of oxytocin in the sheep placenta. The role of OTRs in the capsule during mid-pregnancy remains to be determined.

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Oxytocin Induces Prostaglandin F2α Release in Pregnant Cows: Influence of Gestational Age and Oxytocin Receptor Concentrations1

Cited by 45 publications

References 38 publications

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Uterine peristalsis during the follicular phase of the menstrual cycle: effects of oestrogen, antioestrogen and oxytocin

Regulation of oxytocin receptor in the placentome capsule throughout pregnancy in the ewe: the possible role of oestradiol receptor, progesterone receptor and aromatase

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