Peripheral Plasma Progesterone and the Number of Foetuses in Normal and Superovulated Rabbits

Polidoro, J. P.; Black, D. L.

doi:10.1530/jrf.0.0220493

Cited by 12 publications

(5 citation statements)

References 17 publications

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“…The higher concentrations of progesterone observed during the postovulatory period in does ovulating on Day 14 post partum may have been related to the higher ovulation rate in this group. The corpus luteum represents the only source of progesterone during gestation in rabbits (Thau & Lanman, 1976), although Polidoro & Black (1970) could not show a correlation between numbers of CL in the ovary and progesterone secretion. The animals in the present experiment were, how¬ ever, also lactating and consequently the findings of Polidoro & Black (1970) may not be appli¬ cable.…”

Section: Discussionmentioning

confidence: 83%

“…The corpus luteum represents the only source of progesterone during gestation in rabbits (Thau & Lanman, 1976), although Polidoro & Black (1970) could not show a correlation between numbers of CL in the ovary and progesterone secretion. The animals in the present experiment were, how¬ ever, also lactating and consequently the findings of Polidoro & Black (1970) may not be appli¬ cable. Alternatively, the stage of lactation may alter the metabolic turnover rate of progesterone and thereby influence peripheral concentrations.…”

Section: Discussionmentioning

confidence: 83%

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Effects of reducing the remating interval after parturition on the fertility and plasma concentrations of luteinizing hormone, prolactin, oestradiol-17 and progesterone in lactating domestic rabbits

Lamb¹,

Strachan²,

Henderson³

et al. 1991

Reproduction

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Primiparous crossbred does were remated on Day 1 (n = 15) or 14 (n = 25) post partum and killed on Day 10 post coitum to assess their fertility. Blood samples were taken during the pre- (0-12 h post coitum) and post- (1-10 days post coitum) ovulatory periods and plasma was assayed for luteinizing hormone (LH), prolactin, oestradiol-17 beta and progesterone. Ovulation response was significantly greater (P less than 0.01) and ovulation rate significantly lower (P less than 0.001) in does mated on Day 1 than in those mated on Day 14 post partum. Does failing to ovulate on Day 14 post partum exhibited no preovulatory LH surge and had significantly lower (P less than 0.05) premating concentrations of oestradiol-17 beta and prolactin than those ovulating at this time. No significant differences in hormone concentrations were observed during the preovulatory period between does ovulating on Days 1 and 14 post partum, with the exception of oestradiol-17 beta. Concentrations of this hormone were significantly lower (P less than 0.01) in does mated on Day 1, at 1 h post coitum. We conclude that (i) fertility was affected by the remating interval after parturition, (ii) ovulation failure was associated with an absence of the preovulatory LH surge and a reduction in premating concentrations of oestradiol-17 beta and prolactin and (iii) the lower ovulation rate in early lactation was apparently caused by a reduction in ovarian competence to respond to the gonadotrophic stimulus.

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 83%

Effects of reducing the remating interval after parturition on the fertility and plasma concentrations of luteinizing hormone, prolactin, oestradiol-17 and progesterone in lactating domestic rabbits

Lamb¹,

Strachan²,

Henderson³

et al. 1991

Reproduction

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show abstract

“…Greig et al (1962), contrary to Eton & Short (1960), concluded that values in multigravid women were within the range of values for singleton pregnancies. Also, Polidoro & Black (1970) found that in rabbits there was no difference in progesterone concentration between pregnant controls and superovulated animals, despite increased numbers of corpora lutea and foetuses in the experimental group.…”

Section: Discussionmentioning

confidence: 88%

Progesterone Concentration in the Peripheral Plasma of Pregnant Goats

Irving¹,

Da²,

Knifton³

1972

Journal of Endocrinology

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Plasma progesterone concentration was measured by a competitive protein-binding method in serial samples of jugular venous blood from 21 pregnant goats, 11 with twin and 10 with single foetuses.Progesterone levels in twin pregnancies were significantly greater than in singletons. The mean progesterone concentration (ng/ml plasma) in the twin pregnancies was greatest during the 3rd month of gestation (10\m=.\7 \ m=+-\0\m=.\4 (s.e.m.)) and in the singletons during the 4th month (7\m=.\8 \ m=+-\ 0\m=.\2 (s.e.m.)). There was a significant decrease in mean progesterone concentration in the last month of pregnancy due to a steady decline in the last 7 days before parturition.The mean progesterone concentrations at parturition in five twin and eight single pregnancies were 2\m=.\2\ m=+-\0\m=.\4and 1\m=.\5\ m=+-\0\m=.\2 (s.e.m.) ng/ml plasma respectively; there was no significant difference between these values. In cord blood from nine kids immediately after delivery the progesterone concentration was 0\m=.\9\ m=+-\0\m=.\1 ng/ml.

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“…This is the most likely explanation for the onset of parturition at the normal time on Day 16 since injection of as little as 0-1 mg progesterone on Day 15 has been shown to delay parturition (Siegel & Greenwald, 1975). Plasma progesterone concentrations were found to be elevated after induction of superovulation in gilts (Webel, Reimers & Dziuk, 1975), and in pseudopregnant rats (Horikoshi & Wiest, 1971), but not in pregnant rabbits (Polidoro & Black, 1970). The only other hormone differing from control values in the superovulating hamster was oestradiol-17ß and the differences were not associated with alterations in serum levels of LH or FSH (Table 2).…”

Section: Discussionmentioning

confidence: 97%

Effects of superovulation on fetal development and hormone levels in the pregnant hamster

Greenwald¹

1976

Reproduction

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Treatment of hamsters with 30 i.u. PMSG induced ovulation of 46 ova/animal, 90% of which were fertilized. CL growth was normal. About 27 zygotes/animal implanted and at term (Day 16) the litter size of the PMSG-treated hamsters was 21 compared to the normal number of 10. Parturition occurred at the normal time. Average weight at birth was about 500 mg less for young of PMSG-treated mothers than for controls. Differences were found in the serum progesterone and oestradiol concentrations of the treated and control hamsters, but serum FSH and LH levels were similar.

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Peripheral Plasma Progesterone and the Number of Foetuses in Normal and Superovulated Rabbits

Cited by 12 publications

References 17 publications

Effects of reducing the remating interval after parturition on the fertility and plasma concentrations of luteinizing hormone, prolactin, oestradiol-17 and progesterone in lactating domestic rabbits

Effects of reducing the remating interval after parturition on the fertility and plasma concentrations of luteinizing hormone, prolactin, oestradiol-17 and progesterone in lactating domestic rabbits

Progesterone Concentration in the Peripheral Plasma of Pregnant Goats

Effects of superovulation on fetal development and hormone levels in the pregnant hamster

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