Sexual Receptivity and Fertility of Female Rats that are in Androgen Induced Persistent Vaginal Estrus

Ericsson, R. J.; Baker, V. F.

doi:10.3181/00379727-122-31059

Cited by 11 publications

(7 citation statements)

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“…Our failure to observe pregnancies in the androgenized females in Experiment 1 is contrary to the report of Ericsson and Baker (1966) that approximately half of their animals exhibiting PVE as a consequence of neonatal androgenization became pregnant when mated. A major procedural difference between that study and Experiment 1 is that in the former females cohabited with males overnight on one or more occasions whereas in the latter study only a single relatively limited mating encounter was permitted.…”

Section: Methodscontrasting

confidence: 99%

“…Further, androgenized and control animals mated from maturity onward remain reproductively competent longer than animals not permitted to engage in reproductive behaviors earlier in life (Gerall et al, 1980). Pregnancies have also been reported to occur in animals exhibiting PVE as a consequence of neonatally injected TP (Ericsson & Baker, 1966). In that study, neonatally androgenized female rats were housed overnight with males.…”

mentioning

confidence: 93%

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Responses to copulatory stimulation in neonatally androgenized female rats.

Se¹,

Lehman²,

Oswalt³

1982

Journal of Comparative and Physiological Psychology

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Section: Methodscontrasting

confidence: 99%

mentioning

confidence: 93%

Responses to copulatory stimulation in neonatally androgenized female rats.

Se¹,

Lehman²,

Oswalt³

1982

Journal of Comparative and Physiological Psychology

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“…Neonatal androgenization will cause an emergent persistent estrus and has been used in the past as a model to investigate fertility in such anovulatory animals mated following an induced ovulation. The data have been somewhat equivocal (e.g., Witschi and Pfeiffer, 1935; Ericsson and Baker, 1966; Dorner and Fatschel, 1970; Sawada, 1987), but an observed decline in fertility in these persistent estrus females has been reported to be attributable to the size of the initial dose of androgen employed (Kramen and Johnson, 1971), or the lack of sufficient priming (Sawada, 1987). Nevertheless, in a toxicology study, it would be unclear if any effects on litter size in those pregnant females previously exhibiting a persistent estrus were due to a direct effect of toxicant exposure, to the anovulatory status prior to a mating‐induced ovulation, or a combination of both.…”

Section: Application Of Vaginal Cytological Assessments In Toxicologimentioning

confidence: 99%

The rodent estrous cycle: characterization of vaginal cytology and its utility in toxicological studies

Goldman

Murr

Cooper

2007

Birth Defects Research Pt B

680

497

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While an evaluation of the estrous cycle in laboratory rodents can be a useful measure of the integrity of the hypothalamic-pituitary-ovarian reproductive axis, it can also serve as a way of insuring that animals exhibiting abnormal cycling patterns are disincluded from a study prior to exposure to a test compound. Assessment of vaginal cytology in regularly cycling animals also provides a means to establish a comparable endocrine milieu for animals at necropsy. The procedure for obtaining a vaginal smear is relatively non-invasive and is one to which animals can become readily accustomed. It requires few supplies, and with some experience the assessments can be easily performed in fresh, unstained smears, or in fixed, stained ones. When incorporated as an adjunct to other endpoint measures, a determination of a female's cycling status can contribute important information about the nature of a toxicant insult to the reproductive system. In doing so, it can help to integrate the data into a more comprehensive mechanistic portrait of the effect, and in terms of risk assessment, may provide some indication of a toxicant's impact on human reproductive physiology.

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“…Studies of the role of ovarian steroids in controlling the nocturnal prolactin surges induced by cervical stimulation suggest that in the absence of ovarian progesterone, nightly prolactin surges are maintained for no more than 6 days (Freeman & Sterman, 1978;Murakami, Takahashi & Suzuki, 1979). The occasional pregnancies which result from the mating of aged PVO animals are probably the result of mating-induced ovulations similar to those observed for mating rats made PVO by exposure to constant illumination (Dempsey & Searles, 1943) or by neonatal androgenization (Ericsson & Baker, 1966). In the one rat in PVO which became pregnant in the present study plasma concentrations of progesterone were lower on day 3 than in old/cyclic rats which did not become pregnant.…”

Section: Discussionmentioning

confidence: 80%

Plasma Prolactin and Progesterone Responses to Mating Are Altered in Aged Rats

Hendricks¹,

Blake²

1981

Journal of Endocrinology

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The effects of varying amounts of copulatory stimulation on patterns of plasma concentrations of prolactin and progesterone were evaluated in 3- and 12-month-old female rats. The 12-month-old group included rats which still exhibited oestrous cycles and rats in persistent vaginal oestrus (PVO). The extent of copulatory stimulation was defined by the number of intromissions received during mating: less than or equal to 5, 15 or greater than 50. Blood samples were drawn over the 8 days after mating through a cannula inserted into the right external jugular vein. Plasma from the samples was assayed for prolactin and progesterone. In aged but still cyclic rats, pregnancy rates were positively correlated with the number of intromissions received during mating. Only one rat in PVO became pregnant. All animals which became pregnant and rats in PVO which, after mating, exhibited a disruption of the pattern of PVO, showed the nocturnal surge of plasma prolactin characteristic of pregnant and pseudopregnant rats. While these surges persisted until day 8 after mating in pregnant animals, they were absent by this time in the rats in PVO. Prolactin surges were present in some but not all of the aged rats which did not become pregnant. Progesterone concentrations were raised in all pregnant animals except the one pregnant rat in PVO and, while not related to the number of intromissions, concentrations were higher 8 days after mating in young compared with those in aged pregnant rats. Plasma progesterone was low in rats in PVO regardless of disruption of the pattern of PVO. We have concluded that the failure of limited copulatory stimulation to induce pregnancy in older rats results, at least in part, from its failure to initiate nocturnal prolactin surges. Nevertheless, our data suggest that matings which are not experimentally limited should provide ample stimulation to establish such surges. Although reduced plasma concentrations of prolactin and progesterone at pro-oestrus and reduced plasma progesterone through part of gestation may contribute to decreasing fertility in aged rats, other unidentified factors appear to be involved in mediating the capacity of extensive copulatory stimulation to induce pregnancy in these animals.

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Sexual Receptivity and Fertility of Female Rats that are in Androgen Induced Persistent Vaginal Estrus

Cited by 11 publications

References 0 publications

Responses to copulatory stimulation in neonatally androgenized female rats.

Responses to copulatory stimulation in neonatally androgenized female rats.

The rodent estrous cycle: characterization of vaginal cytology and its utility in toxicological studies

Plasma Prolactin and Progesterone Responses to Mating Are Altered in Aged Rats

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