Effects of Oestradiol and Prostaglandin F2  on the Timing of Parturition in the Rat

Dukes, M.; Chester, Rosemary; Atkinson, Patricia

doi:10.1530/jrf.0.0380325

Cited by 23 publications

(16 citation statements)

References 11 publications

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“…PGF2a, given on day 20 of pregnancy, induced premature delivery on day 22 as pre viously reported by Dukes et al [7]. PGF2a produced a small increase in serum bilirubin concentrations in neonatal rats but not to the extent seen with oxytocin.…”

Section: Discussionsupporting

confidence: 69%

“…For this reason, normal SpragueDawley rather than Gunn rats, the latter with a deficiency of liver glucuronyl transferase, were used. The injection schedules were based on information that oxytocin [9] and prostaglandin (PGF2a) [7] can shorten gesta tion in the rat. This model might prove useful for the study of the mechanism(s) by which these drugs could produce neonatal hyperbilirubinaemia.…”

Section: Introductionmentioning

confidence: 99%

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Hyperbilirubinaemia in Neonatal Rats after Oxytocin or Prostaglandin F<sub>2α</sub> Treatment of Pregnant Rats

Hollingsworth¹,

Oyewo²

1985

Neonatology

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Serum bilirubin concentrations were investigated in neonatal rats. High concentrations were found on day 1 falling to adult values by day 4. Oxytocin (500 IU/kg) given subcutaneously to the dams on day 22 of pregnancy increased bilirubin concentrations in neonatal rats. This dose of oxytocin shortened gestational length but increased the neonatal death rate. Oxytocin (500 IU/kg) also increased uterine contractions on day 22 of pregnancy, measured using intrauterine balloons inserted on day 19 of pregnancy. Rats delivered by Caesarian section at the same gestational age as the oxytocin-treated group did not exhibit hyperbilirubinaemia. Prostaglandin F_2α (300 μg/kg) administered intramuscularly on day 20 of pregnancy was found to advance parturition and produced a small rise in serum bilirubin concentrations in neonatal rats. The rat could serve as a model for investigating the mechanisms of neonatal hyperbilirubinaemia which has been suggested to occur after the use of oxytocin or prostaglandins in the human.

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Section: Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Hyperbilirubinaemia in Neonatal Rats after Oxytocin or Prostaglandin F<sub>2α</sub> Treatment of Pregnant Rats

Hollingsworth¹,

Oyewo²

1985

Neonatology

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“…Abe (1970) gives evidence that the rat uterus has both alpha and beta receptors and that their number in that organ may be steroid-dependent (Williams and Lefkowitz, 1977 ;Roberts et al, 1977 Watson, 1974 ;Dukes et al, 1974 ;Buckle and Nathanielsz, 1975 ;Strauss, 1975) which is controlled by estrogen secretion (Yoshinaga et al, 1969 ; ;Waynforth et a/., 1972 ; Labhsetwar and Watson, 1974 ;De Lauzon et al, 1974), estrogen being necessary for the normal progress of parturition in rat (Jost, 1959 ;Acker, 1969 ;Csapo and Wiest, 1969 ;Catala and Deis, 1973). Furthermore, labor is sustained by secretion of PGF 2a (Dukes et al, 1974 ;Labhsetwar and Watson, 1974 ;Shaikh et al, 1977). Thus, it may be postulated that our experiments were done under uterine estrogenic impregnation at a time when PGF 2a secretion was active and progesterone level was falling.…”

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confidence: 99%

Effect of stress on the course of labor and parturition time in normal or adrenalectomized rats

Bosc¹,

Nicolle²

1979

Ann. Biol. anim. Bioch. Biophys.

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Summary. We report two experiments studying the effect of stress on the course of labor and on the time of parturition in the parturient rat. In the first experiment, different stresses were applied after expulsion of the first fetus. A simple manipulation of the female or a change of territory did not modify the whole expulsion phase but increased variability in the birth of the second fetus. By comparison, a strong stress lengthened the duration of expulsion and influenced the time intervals between the first births. A comparison of these results with those obtained after adrenalectomy indicated that the inhibitory effect of a strong stress was probably due to maternal adrenal epinephrin secretion. In the second experiment, a stress was applied before labor in normal rats submitted to two light regimes. In these conditions, the treatment essentially stimulated the last parturitions, which occurred earlier than in control animals.The course of labor and the time of fetal expulsion are known to be influenced by an environmental change or by any event felt as stress. The bitch, for example, often has a labor affected by a disturbance of its usual life conditions (Bleicher, 1962 ;Freak, 1962). In domestic animals such as the pig (Signoret, 1969) Figure 4, which includes the 5 groups of normal rats, shows that this perinatal mortality is related to duration of the labor expulsion phase.After adrenalectomy, with or without a stress after expulsion of the first fetus (lots A-and A-+ S), the total lenght of the expulsion phase did not differ from that of the normal rats (lot N) (P > 0.05). But figure 5 shows that the mean increase of expulsion time at each additional birth was slightly higher in the adrenalectomized rats than in the normal ones. This was partially due to the greater variability of the first two intervals between the first three births ( fig. 5) in lots A-and A-+ S. As the number of animals was too small in these lots, interval distributions have not been compared to the control. On the other hand, figure 5 shows the close evolution of the mean increase of expulsion time at each additional birth in normal rats submitted to a strong stress (lot 5) fig. 3).These results demonstrate that a stress at this stage of pregnancy has not only an inhibitory effect on the course of labor, as has often been emphasized (Newton et al., 1968 ; Naaktgeboren and Bontekoe, 1976), they also show this effect can be attributed to epinephrin secretion since 5 !.g of this catecholamine produced the strong stress response of normal rats in adrenalectomized ones (fig. 5). These data agree with observations obtained on the uterine activity of parturient rabbit or sheep (Naaktgeboren and Bontekoe, 1976). But epinephrin causes three types of response in the myometrium and it has been stated that they depend on the hormonal status of the animal. Abe (1970) gives evidence that the rat uterus has both alpha and beta receptors and that their number in that organ may be steroid-dependent (Williams and Lefkowitz, 1977 ;Roberts et...

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“…However, the decline of plasma progesterone is only one of a series of endocrine events that culminate in parturition. These include an increase in which has luteolytic actions, increases in PGF , 2␣ plasma estradiol and relaxin that prepare the uterus for response to oxytocin, and the release of oxytocin that acts on the pregnant uterus (Dukes et al, 1974;Labhsetwar & Watson, 1974;Lincoln & Porter, 1979;Murakami et al, 1987). Timing of these endocrine events does not seem to be under the control of photoperiodic stimulation during the last few days before parturition because drastic changes in photoperiod, including constant light or darkness, do not appear to alter the time of parturition.…”

Section: Discussionmentioning

confidence: 99%

A method for regulating the duration of pregnancy and the time of parturition in Sprague-Dawley rats (Charles River CD strain)

Mayer

Rosenblatt

1998

Dev. Psychobiol.

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A method of shifting the dark phase of the 12/12 hr photoperiod cycle on Day 7 of pregnancy is described for regulating the duration of pregnancy to 22 days and assuring that most parturitions take place between 1100 and 1500 hr. This method, in addition, has the added convenience that matings can occur during normal laboratory hours between 0700 and 1900 hr during the dark phase of the photoperiodic cycle. Litter sizes are normal (mostly 14–16 pups) and postpartum estrus behavior occurs at the normal interval of 4 to 11½ hr after parturition. © 1998 John Wiley & Sons, Inc. Dev Psychobiol 32: 131–136, 1998

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Effects of Oestradiol and Prostaglandin F2 on the Timing of Parturition in the Rat

Cited by 23 publications

References 11 publications

Hyperbilirubinaemia in Neonatal Rats after Oxytocin or Prostaglandin F<sub>2α</sub> Treatment of Pregnant Rats

Hyperbilirubinaemia in Neonatal Rats after Oxytocin or Prostaglandin F<sub>2α</sub> Treatment of Pregnant Rats

Effect of stress on the course of labor and parturition time in normal or adrenalectomized rats

A method for regulating the duration of pregnancy and the time of parturition in Sprague-Dawley rats (Charles River CD strain)

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