Advancement of Meiotic Resumption in Graafian Follicles Reduces Fertility in the Rat

Mattheij, J.A.M.; Swarts, J.J.M.; Heijden, A.J.H. van der; Hervoort, A.L.B. van; Kusters, I.C.

doi:10.1159/000292611

Cited by 10 publications

(9 citation statements)

References 21 publications

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“…However, the present data show that after a considerably reduced LH surge either all graafian follicles ovulated or the graafian follicles appeared unaffected; they contained an oocyte in germinal vesicle stage and were not luteinized. The explanation of the discrepancy between Mattheij et al (9,10) and the present results may be that in the former studies injection of LH caused a steep and short-lasting (less than 60 min) increase of LH in the plasma, whereas in the present study the rats with a partially suppressed LH surge had a slightly increased LH level for several hours. The discrepancy may also be due to the fact that Mattheij et al (9,10) injected LH 8 h before the presumed onset of the LH surge.…”

Section: Discussioncontrasting

confidence: 97%

“…The explanation of the discrepancy between Mattheij et al (9,10) and the present results may be that in the former studies injection of LH caused a steep and short-lasting (less than 60 min) increase of LH in the plasma, whereas in the present study the rats with a partially suppressed LH surge had a slightly increased LH level for several hours. The discrepancy may also be due to the fact that Mattheij et al (9,10) injected LH 8 h before the presumed onset of the LH surge. Conceivably, at that time fewer LH receptors were present in the granulosa layer of the graafian follicles than at the beginning of the presumed onset of the LH surge (26).…”

Section: Discussioncontrasting

confidence: 97%

“…Luteinizing hormone also induces meiotic resumption of the oocyte and can induce premature luteinization in graafian follicles. In graafian follicles, meiotic resumption and luteinization have been shown to start after a dose of LH smaller than needed for ovulation (9,10). If restraint stress partially suppresses the LH surge, it may conceivably induce either meiotic resumption without subsequent ovula¬ tion or luteinized unruptured follicles (LUF).…”

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confidence: 99%

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Effect of restraint stress on the preovulatory luteinizing hormone profile and ovulation in the rat

Roozendaal

Swarts

Wiegant

et al. 1995

European Journal of Endocrinology

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Plasma profiles of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured during restraint stress on the day of pro-oestrus; these profiles were considered in relation to ovulation rate on the next day. Rats bearing a permanent jugular vein cannula were subjected to restraint, which was started 0, 1 or 2 h before the presumed onset of the LH surge and ended just before the beginning of the dark period. Exposure to restraint resulted in a suppression of the secretion of both gonadotrophins on the day of pro-oestrus. Suppression of the LH surge was virtually complete (plasma LH < or = 0.2 ng/ml) in 15 out of 32 stressed rats, and the ovaries of these rats contained graafian follicles with oocytes in germinal vesicle stage. In these rats, the LH surge did not occur 24 h later. In the remaining 17 rats, restraint resulted in a considerable suppression of the LH surge. Of these rats, five had an ovulation rate of 100% and four ovulated partially. In unruptured follicles of the latter, the oocyte had not resumed meiosis and the follicle wall was not luteinized. In the remaining eight rats with a reduced LH surge, ovulations had not occurred and graafian follicles were unaffected. The results of this study indicate that during pro-oestrus restraint stress suppresses and does not delay the release of preovulatory gonadotrophins. Partial suppression of LH by restraint does not result in induction of meiotic resumption without subsequent ovulation or in luteinized unruptured follicles.

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Section: Discussioncontrasting

confidence: 97%

Section: Discussioncontrasting

confidence: 97%

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confidence: 99%

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Effect of restraint stress on the preovulatory luteinizing hormone profile and ovulation in the rat

Roozendaal

Swarts

Wiegant

et al. 1995

European Journal of Endocrinology

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“…Serial sections (10 pm thick) were stained with haematoxylin and eosin, and mounted in DePeX (BDH Laboratory Supplies, Poole, Dorset, UK). In this way the numbers of ovulated eggs, corpora lutea and large atretic follicles could easily be quantified (for details see Mattheij et al 1993). …”

Section: Histologymentioning

confidence: 99%

Effect of hypothyroidism on the pituitary-gonadal axis in the adult female rat

Mattheij¹,

Swarts²,

Lokerse³

et al. 1995

Journal of Endocrinology

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The pituitary-ovarian axis was studied after withdrawal of thyroid hormone in 131I-radiothyroidectomized adult female rats. Oestrous cycles became prolonged and irregular within 2 weeks after the supply of thyroid hormone was stopped. If an LH surge occurred in hypothyroid rats on the day of vaginal pro-oestrus it was significantly greater in rats which had been made hypothyroid for 4-5 weeks than in controls; in hypothyroid rats with an LH surge on pro-oestrus, plasma progesterone showed a rise similar to that in controls at pro-oestrus; the ovulation rate was decreased in hypothyroid rats. About half of the rats from which blood was sampled daily in the afternoon between 7 and 18 days after tri-iodothyronine (T3) withdrawal had 1 day of pro-oestrus; on this day the LH surge was higher than in controls. On days 2 and 1 before and days 1 and 2 after this pro-oestrus, plasma progesterone was similar to that of controls on days 2 and 1 before and days 1 and 2 after pro-oestrus respectively. However, progesterone was higher in the period before and after these days. The other hypothyroid rats showed no pro-oestrus and no LH surge during this period, while their plasma progesterone levels were high on all days. On the morning of day 10 after T3 withdrawal and 5 days after the preceding pro-oestrus, most hypothyroid rats had high progesterone and low oestradiol plasma levels.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…In the rat, dosages of LH incapable of causing ovulation also stimulate oocyte maturation. Advancing the time oocyte maturation by as little as eight hours with this treatment resulted in low fertility (Mattheij et al, 1993;Dekel et al, 1995). Therefore, abnormal patterns of secretion of LH can influence oocyte function independently of ovulation.…”

Section: Gonadotropinsmentioning

confidence: 99%

Oocyte morphology and estrogen concentrations following a reduction in progesterone in beef cattle

Taft¹,

Robert²

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Low dosages of progestogens promote persistent follicles, high systemic estrogen and low fertility. The objectives of this study were to determine effects of a reduction in progesterone on (1) morphology of oocytes and intrafollicular concentrations of estradiol. Cows on low progesterone (n=12) received used intravaginal progesterone inserts on d 4 after estrus and prostaglandin (PG) F 2α (25 mg, i.m.) on d 6. Control animals (n=12) received saline on d6. The oocyte and follicular fluid were recovered from the largest follicle on d 8 or d 10. Serum estradiol was lower during d 4-6 but greater (P < .01) during d 7-10 in cows treated with progesterone inserts and PGF 2α while the largest follicle was larger in treated cows on day 10 only (14 vs. 12 mm; P < .05). Intrafollicular concentrations of estrogen were greater in treated than in control cows (990± 87 vs 191±106; P < .01). Progesterone in follicular fluid (mean = 42 ng/ml) did not differ. Oocytes were observed in oocyte nuclear stage I in the control group on d 8. All other oocytes were in nuclear stage II. In addition, the degree of clumping of mitochondria, the percentage of intact cumulus cell processes and percentage of normally shaped mitochondria was greater in oocytes from d 8 control cows than in all other groups. Changes in concentrations of estradiol and oocyte morphology typically associated with the preovulatory period had occurred within 2 d after a reduction in progesterone, even when low peripheral concentrations of progesterone were maintained. These earliest stages of oocyte maturation occurred in response to a reduction in progesterone. Similar changes in oocyte morphology were observed in control animals by d 10 of the estrous cycle, probably representing the onset of atresia. iii ACKNOWLEDGEMENTS I would like to thank my mentor, Dr. Keith Inskeep, for his guidance, wisdom and support that have helped me complete my program and grow as a scientist. I would also like to thank the other members of my committee Drs.

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Advancement of Meiotic Resumption in Graafian Follicles Reduces Fertility in the Rat

Cited by 10 publications

References 21 publications

Effect of restraint stress on the preovulatory luteinizing hormone profile and ovulation in the rat

Effect of restraint stress on the preovulatory luteinizing hormone profile and ovulation in the rat

Effect of hypothyroidism on the pituitary-gonadal axis in the adult female rat

Oocyte morphology and estrogen concentrations following a reduction in progesterone in beef cattle

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