Control of ovarian follicular growth and maturation by the corpus luteum and the placenta during pregnancy in sheep

Reproduction ◽  
2000 ◽  
Vol 120 (1) ◽  
pp. 151-158 ◽  
Author(s):  
M. Driancourt ◽  
J Fevre ◽  
J Martal ◽  
K. Al-Gubory
Keyword(s):  
Corpus Luteum ◽  
Follicular Growth ◽  
Ovarian Follicular Growth

Control of ovarian follicular growth and maturation by the corpus luteum and the placenta during pregnancy in sheep

Reproduction ◽  
2000 ◽  
pp. 151-158 ◽  
Author(s):  
MA Driancourt ◽  
J Fevre ◽  
J Martal ◽  
KH Al-Gubory
Keyword(s):  
Caesarean Section ◽  
Corpus Luteum ◽  
Late Pregnancy ◽  
Aromatase Activity ◽  
Follicular Growth ◽  
Mating Experiment ◽  
The Mean ◽  
High Concentrations ◽  
Ovarian Follicular Growth

Ovarian follicular growth and maturation and its control throughout pregnancy have not been described fully in sheep. Experiment 1 characterized the size and maturation (steroid production in vitro and aromatase activity) of ovarian follicles obtained at days 20, 50, 80 and 110 of pregnancy compared with those obtained at day 12 of the oestrous cycle. There was no difference in the number of small follicles (< 3 mm in diameter) between cyclic and pregnant ewes, regardless of the stage of pregnancy. There was a marked reduction (P < 0.01) in the number of medium follicles (3-5 mm) starting at day 80 of pregnancy. Large follicles (> 5 mm) were not detected at day 110 of pregnancy. In vitro testosterone output by follicles was constant throughout pregnancy. Oestradiol output remained steady until day 80, but decreased markedly at day 110 of pregnancy. This decrease was associated with a reduction in aromatase activity in follicles obtained at this stage. Experiment 2 examined the effect of administration of high concentrations of progesterone between day 100 and day 120 after mating on resumption of follicular growth in ewes that underwent Caesarean section at day 99 of pregnancy. In ewes that underwent Caesarean section, progesterone supplementation was successful in mimicking the profile found in pregnant ewes, but did not prevent re-initiation of follicular growth, as demonstrated by the presence of large follicles (> 5 mm) at day 120 after mating. Experiment 3 examined the effects of PGF(2alpha)-induced regression of the corpus luteum of day 100 of pregnancy on resumption of follicular growth. High concentrations of PGF(2alpha) (0.28 mg kg(-1) body weight) administrated at day 100 of pregnancy were required to initiate regression of the corpus luteum. At day 120 after mating, the mean (+/- SEM) diameter of the largest follicle in PGF(2alpha)-treated ewes (3.40 +/- 0.47 mm) was significantly greater (P < 0.05) than that in control pregnant ewes (2.52 +/- 0.34 mm). Experiment 4 examined the effect of removal of the fetus and of the corpus luteum at day 100 of pregnancy on resumption of ovulation. Removal of the corpus luteum by PGF(2alpha) treatment at the time of removal of the fetus resulted in earlier occurrence of short luteal phases (27.8 versus 40.6 days, PGF(2alpha)-treated versus non-treated) but did not alter the timing of the first normal luteal phases (41 days). In conclusion, the results from these experiments indicate that placental compounds play a major role in inhibiting follicular growth and maturation during late pregnancy in sheep.

scholarly journals The role of IGFs in the regulation of ovarian follicular growth in the brushtail possum (Trichosurus vulpecula)

Reproduction ◽  
2010 ◽  
Vol 140 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Jennifer L Juengel ◽  
Lisa J Haydon ◽  
Brigitta Mester ◽  
Brian P Thomson ◽  
Michael Beaumont ◽  
...  
Keyword(s):  
Granulosa Cell ◽  
Granulosa Cells ◽  
Cell Function ◽  
Antral Follicle ◽  
Brushtail Possum ◽  
Follicular Growth ◽  
Theca Cells ◽  
Ovarian Follicular Growth

IGFs are known to be key regulators of ovarian follicular growth in eutherian mammals, but little is known regarding their role in marsupials. To better understand the potential role of IGFs in the regulation of follicular growth in marsupials, expression of mRNAs encoding IGF1, IGF2, IGF1R, IGF-binding protein 2 (IGFBP2), IGFBP4 and IGFBP5 was localized by in situ hybridization in developing ovarian follicles of the brushtail possum. In addition, the effects of IGF1 and IGF2 on granulosa cell function were tested in vitro. Both granulosa and theca cells synthesize IGF mRNAs, with the theca expressing IGF1 mRNA and granulosa cell expressing IGF2 mRNA. Oocytes and granulosa cells express IGF1R. Granulosa and theca cells expressed IGFBP mRNAs, although the pattern of expression differed between the BPs. IGFBP5 mRNA was differentially expressed as the follicles developed with granulosa cells of antral follicles no longer expressing IGFBP5 mRNA, suggesting an increased IGF bioavailability in the antral follicle. The IGFBP protease, PAPPA mRNA, was also expressed in granulosa cells of growing follicles. Both IGF1 and IGF2 stimulated thymidine incorporation but had no effect on progesterone production. Thus, IGF may be an important regulator of ovarian follicular development in marsupials as has been shown in eutherian mammals.

Gonadotrophins and Ovarian-Follicular Growth

1978 ◽  
Vol 5 (2) ◽  
pp. 363-373
Author(s):  
JOANNE S. RICHARDS ◽  
RIAZ FAROOKHI
Keyword(s):  
Follicular Growth ◽  
Ovarian Follicular Growth

scholarly journals Use of ultrasound biomicroscopy to evaluate induced ovarian follicular growth and ovulation in mice

2011 ◽  
Vol 45 (4) ◽  
pp. 254-258 ◽  
Author(s):  
Paulo H A Campos-Junior ◽  
Cristina A Silva ◽  
Joao G V Grazia ◽  
Milena B P Soares ◽  
Ricardo R Santos ◽  
...  
Keyword(s):  
Ultrasound Biomicroscopy ◽  
Follicular Growth ◽  
Ovarian Follicular Growth

Mast cell histamine and ovarian follicular growth in the lizardAnolis carolinensis

1975 ◽  
Vol 193 (3) ◽  
pp. 343-351 ◽  
Author(s):  
Richard E. Jones ◽  
Richard R. Tokarz ◽  
Jan J. Roth ◽  
James E. Platt ◽  
Allan C. Collins
Keyword(s):  
Mast Cell ◽  
Follicular Growth ◽  
Ovarian Follicular Growth

Ovarian follicular growth and FSH secretion following a timed injection of progesterone in cows

1996 ◽  
Vol 45 (1) ◽  
pp. 325 ◽  
Author(s):  
B.R. Lindsey ◽  
M.E. Wehrman ◽  
E.J. Melvin ◽  
J.A. Quintal ◽  
F.N. Kojima ◽  
...  
Keyword(s):  
Follicular Growth ◽  
Ovarian Follicular Growth
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