Effects of delaying the LH surge and altering LH secretion on plasma hormones and embryo production in heifers superstimulated with FSH

Carrière, Paul D.; Kohram, Hamid; Price, Christopher A.; Durocher, J.; Guilbault, L.A.

doi:10.4141/a01-061

Cited by 4 publications

(1 citation statement)

References 42 publications

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“…Earlier studies have found that a delay in LH surge of 11.4 h in heifers [28] and 24-48 h in mice [29,30] reduces fertilization and implantation rates and increases embryonic death and chromosome abnormalities [28][29][30]. In superovulation models of cattle, a delayed surge of 24-48 h was found to be associated with compromised follicular development [31], decreased ovulation rate, and lowered rate of embryo production [32]. It is unclear if a short delay of 3 h, such as that seen in this study, would have physiological impact on oocyte quality.…”

Section: Consequences Of Delayed Lh Surgementioning

confidence: 99%

Fetal Programming: Testosterone Exposure of the Female Sheep During Midgestation Disrupts the Dynamics of Its Adult Gonadotropin Secretion During the Periovulatory Period1

Savabieasfahani¹,

Lee²,

Herkimer³

et al. 2005

Biology of Reproduction

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Prenatal exposure of the female sheep to excess testosterone (T) leads to hypergonadotropism, multifollicular ovaries, and progressive loss of reproductive cycles. We have determined that prenatal T treatment delays the latency of the estradiol (E2)-induced LH surge. To extend this finding into a natural physiological context, the present study was conducted to determine if the malprogrammed surge mechanism alters the reproductive cycle. Specifically, we wished to determine if prenatal T treatment 1) delays the onset of the preovulatory gonadotropin surge during the natural follicular phase rise in E2, 2) alters pulsatile LH secretion and the dynamics of the secondary FSH surge, and 3) compromises the ensuing luteal function. Females prenatally T-treated from Day 60 to Day 90 of gestation (147 days is term) and control females were studied when they were approximately 2.5 yr of age. Reproductive cycles of control and prenatally T-treated females were synchronized with PGF2alpha, and peripheral blood samples were collected every 2 h for 120 h to characterize cyclic changes in E2, LH, and FSH and then daily for 14 days to monitor changes in luteal progesterone. To assess LH pulse patterns, blood samples were also collected frequently (each 5 min for 6 h) during the follicular and luteal phases of the cycle. The results revealed that, in prenatally T-treated females, 1) the preovulatory increase in E2 was normal; 2) the latencies between the preovulatory increase in E2 and the peaks of the primary LH and FSH surges were longer, but the magnitudes similar; 3) follicular-phase LH pulse frequency was increased; 4) the interval between the primary and secondary FSH surges was reduced but there was a tendency for an increase in duration of the secondary FSH surge; but 5) luteal progesterone patterns were in general unaltered. Thus, exposure of the female to excess T before birth produces perturbances and maltiming in periovulatory gonadotropin secretory dynamics, but these do not produce apparent defects in cycle regularity or luteal function. To reveal the pathologies that lead to the eventual subfertility arising from excess T exposure during midgestation, studies at older ages must be conducted to assess if there is progressive disruption of neuroendocrine and ovarian function.

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Section: Consequences Of Delayed Lh Surgementioning

confidence: 99%

Fetal Programming: Testosterone Exposure of the Female Sheep During Midgestation Disrupts the Dynamics of Its Adult Gonadotropin Secretion During the Periovulatory Period1

Savabieasfahani¹,

Lee²,

Herkimer³

et al. 2005

Biology of Reproduction

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Developmental programming in sheep: Administration of testosterone during 60–90 days of pregnancy reduces breeding success and pregnancy outcome

et al. 2007

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Developmental Programming: Prenatal and Postnatal Contribution of Androgens and Insulin in the Reprogramming of Estradiol Positive Feedback Disruptions in Prenatal Testosterone-Treated Sheep

et al. 2012

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Prenatal testosterone (T) excess compromises the estradiol (E(2)) positive feedback. This study tested the hypothesis that antagonizing androgen action or improving insulin sensitivity prenatally would prevent positive feedback disruptions from developing, whereas postnatal intervention with androgen antagonist or insulin sensitizer would ameliorate the severity of disruptions in prenatal T-treated females. The E(2) positive feedback response was tested at 16 wk of age in the following groups of animals: 1) control, 2) prenatal T, 3) prenatal T plus the androgen antagonist, flutamide, 4) prenatal T plus insulin sensitizer, rosiglitazone, 5) prenatal T and postnatal androgen antagonist, and 6) prenatal T and postnatal insulin sensitizer (n = 7-21 animals/group). Prenatal T treatment involved the administration of T propionate (100 mg, im) twice weekly from d 30 to 90 of gestation. Prenatal interventions involved daily sc administration of androgen antagonist (15 mg/kg) or oral administration of insulin sensitizer (8 mg) for the same duration. Postnatal treatments began at 8 wk of age and involved daily oral administration of androgen antagonist (15 mg/kg) or insulin sensitizer (0.11 mg/kg). None of the prenatal/postnatal interventions increased number of animals responding or prevented the time delay in LH surge response to the E(2) positive feedback challenge. In contrast, the postnatal treatment with androgen antagonist or insulin sensitizer increased total LH released in response to E(2) positive feedback challenge, compared with the T animals. Overall, these interventional studies indicate that timing and magnitude of the LH surge are programmed by different neuroendocrine mechanisms with postnatal androgens and insulin determining the size and prenatal estrogen likely the timing of the LH surge.

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Effects of delaying the LH surge and altering LH secretion on plasma hormones and embryo production in heifers superstimulated with FSH

Cited by 4 publications

References 42 publications

Fetal Programming: Testosterone Exposure of the Female Sheep During Midgestation Disrupts the Dynamics of Its Adult Gonadotropin Secretion During the Periovulatory Period1

Fetal Programming: Testosterone Exposure of the Female Sheep During Midgestation Disrupts the Dynamics of Its Adult Gonadotropin Secretion During the Periovulatory Period1

Developmental programming in sheep: Administration of testosterone during 60–90 days of pregnancy reduces breeding success and pregnancy outcome

Developmental Programming: Prenatal and Postnatal Contribution of Androgens and Insulin in the Reprogramming of Estradiol Positive Feedback Disruptions in Prenatal Testosterone-Treated Sheep

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