The Effects of Hysterectomy on the System of Sex Organs and on the Periodicity of the Sexual Cycle in the Guinea Pig

Loeb, Leo

doi:10.1152/ajplegacy.1927.83.1.202

Cited by 59 publications

(36 citation statements)

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“…The role of the uterus in determining the lifespan of the CL was first demonstrated in guinea pigs by showing that CL were maintained after hysterectomy (Loeb, 1927). In ruminants, a clear demonstration of the role of the uterus in luteolysis was published in 1956 by using hysterectomy of both sheep and cattle (Wiltbank and Casida, 1956).…”

Section: Period Ii: Normal Luteolysis: Role Of Uterus and Pgf -Days 1mentioning

confidence: 99%

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: Period Ii: Normal Luteolysis: Role Of Uterus and Pgf -Days 1mentioning

confidence: 99%

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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“…The effects of hysterectomy on the ovaries, mammary gland and oestrous behaviour of the unmated guinea-pig were extensively studied by Loeb more than 30 years ago (Loeb, 1923(Loeb, ,1927(Loeb, ,1932Loeb & Kountz, 1928). The principal effect was a persistence of the corpora lutea in a functional condition which resulted in the inhibition of ovulation, the cessation of the dioestrous cycle and the retention of the vaginal epithelium in a secretory state for periods equivalent to or longer than that of pregnancy.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hysterectomy at Different Stages in the Life Cycle of the Corpus Luteum in the Guinea-Pig

Rowlands¹

1961

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Summary. Hysterectomy on the 5th day of the luteal phase inhibited the dioestrous cycle for at least 8 months. The corpora lutea persisted throughout this period and, at the end, contained an appreciable amount of progesterone.Hysterectomy on the 10th day of the luteal phase caused the corpora lutea to enlarge as in pregnancy and to persist for a period about equal to that of gestation.Hysterectomy on the 15th day of the luteal phase prevented the impending ovulation and oestrus in 70 % (24/35) of animals. In these, the major effect was the arrest of the regressive changes in the corpora lutea, which became only slightly enlarged. In the remaining animals, ovulation and oestrus occurred shortly after the operation. The regres¬ sion of the corpora lutea occurred normally but the corpora lutea that formed post-operatively responded in the same way as those in animals operated on the 5th or 10th days of the luteal phase. The nature of the stimulus of hysterectomy on the corpus luteum of the guinea-pig is discussed briefly.

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“…The animals were examined daily for vaginal changes; the first day of vaginal closure after oestrus (corresponding in In the hysterectomized guinea-pig the luteal phase is prolonged and may last 4 months after which a fresh ovulation occurs; this can be accelerated by removal of the corpora lutea (Loeb, 1927). Ovulation during the luteal phase can, however, be induced by lh in untreated hysterectomized females as well as in those where the luteal phase has been experimentally interrupted (Deanesly & Perry, 1965).…”

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confidence: 99%

The Effects of Purified Sheep Luteinizing Hormone on the Guinea-Pig Ovary

Deanesly¹

1966

Reproduction

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Luteinizing hormone (Ovine, from the National Institutes of Health, Bethesda, U.S.A.) has been administered subcutaneously in normal saline (0\m=.\5mg/ml) to female guinea-pigs for a study of The induced and cyclic corpora lutea were examined in three females killed 7 days after the lh injection given on luteal Day 7; the two types were histologically distinguishable. In one female both sets of corpora lutea had regressed and the follicles were pre-ovulatory. In another, both sets still looked large and healthy and in the last the cyclic corpora lutea were shrunken and vacuolated while the induced corpora lutea, in marked contrast, retained eosinophil luteal cells with numerous mitotic figures.303

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The Effects of Hysterectomy on the System of Sex Organs and on the Periodicity of the Sexual Cycle in the Guinea Pig

Cited by 59 publications

References 0 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

Effect of Hysterectomy at Different Stages in the Life Cycle of the Corpus Luteum in the Guinea-Pig

The Effects of Purified Sheep Luteinizing Hormone on the Guinea-Pig Ovary

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