scholarly journals Anti-Müllerian hormone promotes pre-antral follicle growth, but inhibits antral follicle maturation and dominant follicle selection in primates

2016 ◽  
Vol 31 (7) ◽  
pp. 1522-1530 ◽  
Author(s):  
J. Xu ◽  
C.V. Bishop ◽  
M.S. Lawson ◽  
B.S. Park ◽  
F. Xu
Keyword(s):  
Antral Follicle ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Follicle Selection ◽  
Follicle Maturation

scholarly journals Effects of oestradiol and progesterone on secretion of gonadotrophins and health of first wave follicles during the oestrous cycle of beef heifers

Reproduction ◽  
2002 ◽  
pp. 531-541 ◽  
Author(s):  
EJ Austin ◽  
M Mihm ◽  
AC Evans ◽  
JL Ireland ◽  
JJ Ireland ◽  
...  
Keyword(s):  
Growth Factor ◽  
Antral Follicle ◽  
Follicle Development ◽  
Dominant Follicle ◽  
Beef Heifers ◽  
Follicle Diameter ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Follicle Selection ◽  
Intravaginal Device

Antral follicle development in cattle is initially FSH dependent and then LH dependent. The aim of the present study was to determine the effects of oestradiol- and progesterone-induced suppression of FSH and LH on growth and differentiation of first wave follicles. Cyclic heifers (n = 45, n = 6-10 per group) received the following i.m. injections or treatments beginning 30 h after oestrus: (i) saline (controls); (ii) 0.75 mg oestradiol benzoate (ODB); (iii) insertion of a progesterone-releasing intravaginal device (PRID) for 42 h (progesterone); (iv) 0.75 mg oestradiol benzoate plus PRID (ODB plus progesterone); (v) 0.75 mg ODB plus injection of 1 mg Ovagen(TM) at 33, 39 and 45 h after onset of oestrus (ODB plus FSH). In Expt 1, follicle development was monitored by ovarian ultrasonography once a day. In Expt 2, heifers were ovariectomized. Emergence of the first follicle wave and dominant follicle selection were delayed in ODB plus progesterone-treated heifers compared with controls. Interval to nadir FSH concentration was shorter in ODB-, progesterone- and ODB plus progesterone-treated heifers compared with controls. Frequency of LH pulses was unaffected in ODB- or ODB plus FSH-treated heifers, decreased in progesterone-treated heifers and further decreased in ODB plus progesterone-treated heifers. Intrafollicular oestradiol concentrations were lower in the largest follicle from ODB plus progesterone-treated heifers compared with control (66 h) heifers, but follicle diameter and concentrations of insulin-like growth factor binding proteins (IGFBPs) and inhibin forms were unaffected. Treatment with ODB decreased follicular oestradiol concentration in smaller follicles in the cohort. It is concluded that growing cohort follicles are uniformly responsive to increased FSH concentration but differentially responsive to suppressed FSH and LH release, which is consistent with an LH-mediated survival advantage of the largest follicle in the cohort before cessation of the growth of remaining follicles in the cohort occurs.

scholarly journals Necessity for LH in selection and continued growth of the bovine dominant follicle

Reproduction ◽  
2020 ◽  
Vol 159 (5) ◽  
pp. 559-569 ◽  
Author(s):  
Victor E Gomez-León ◽  
O J Ginther ◽  
Rafael R Domingues ◽  
José D Guimarães ◽  
Milo C Wiltbank
Keyword(s):  
Chorionic Gonadotropin ◽  
Acute Treatment ◽  
Gnrh Antagonist ◽  
Underlying Mechanism ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Follicular Wave ◽  
Treatment Data ◽  
Follicle Selection ◽  
Selection Of

Previous research demonstrated that acute treatment with GnRH antagonist, Acyline, allowed follicle growth until ~8.5 mm and no dominant follicle was selected. This study evaluated whether deficient LH was the underlying mechanism for Acyline effects by replacing LH action, using human chorionic gonadotropin (hCG), during Acyline treatment. Holstein heifers (n = 24) during first follicular wave were evaluated by ultrasound and randomized into one of three treatments: Control (saline treatments), Acyline (5 µg/kg Acyline), or Acyline+hCG (Acyline plus 50 IU of hCG at start then 100 IU every 12 h). Pulses of LH were present in Control heifers (9 Pulses/10 h) but not during Acyline treatment. Data were normalized to the transition to diameter deviation (day 0; F1 ~7.5 mm). Diameter deviation of the largest (F1) and the second largest (F2) follicle was not observed in Acyline-treated heifers, whereas control heifers had decreased growth of F2 at F1 ~7.5 mm, indicating deviation. Selection of a single dominant follicle was restored by providing LH activity in Acyline+hCG heifers, as evidenced by F1 and F2 deviation, continued growth of F1, and elevated circulating estradiol. Separation of F1 and F2 occurred 12 h (~7.0 mm) earlier in Acyline+hCG heifers than Controls. Circulating FSH was greater in Acyline than Controls, but lower in Acyline+hCG than Controls after day 1.5. In conclusion, dominant follicle selection and growth after follicle deviation is due to LH action as shown by inhibition of this process during ablation of GnRH-stimulated LH pulses with Acyline and restoration of it after replacement of LH action by hCG treatment.

scholarly journals Influence of uterine bacterial contamination after parturition on ovarian dominant follicle selection and follicle growth and function in cattle

Reproduction ◽  
2002 ◽  
pp. 837-845 ◽  
Author(s):  
IM Sheldon ◽  
DE Noakes ◽  
AN Rycroft ◽  
DU Pfeiffer ◽  
H Dobson
Keyword(s):  
Bacterial Growth ◽  
Bacterial Contamination ◽  
Ovarian Follicle ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Growth Scores ◽  
And Function ◽  
Follicle Selection ◽  
Aerobic And Anaerobic ◽  
Uterine Body

First postpartum dominant follicles are preferentially selected in the ovary contralateral to the previously gravid uterine horn. The aim of the present study was to test the hypothesis that uterine bacterial contamination alters the location of ovarian follicle emergence and selection, and inhibits follicle growth and function. Swabs were collected from the uterine body lumen of cattle on days 7, 14, 21 and 28 after parturition. Bacteria were identified by aerobic and anaerobic culture; bacterial growth was scored semiquantitatively and animals were categorized into standard or high bacterial contamination categories on the basis of the number of colonies detected. Follicular growth and function were monitored by daily transrectal ultrasonography, and estimation of plasma FSH, oestradiol and progesterone concentrations. There was no effect of bacterial contamination on plasma FSH concentration profiles or emergence of the ovarian follicle wave. When uterine bacterial growth scores were high on day 7 or day 21 after parturition, fewer first (1/20 versus 15/50; P < 0.05) or second (1/11 versus 13/32; P < 0.05) dominant follicles were selected in the ipsilateral compared with the contralateral ovary, respectively. The diameter of the first dominant follicle was smaller in animals with a high day 7 bacterial score (P < 0.001), dominant follicle growth was slower (P < 0.05) and oestradiol secretion was decreased (P < 0.05). The present study provides evidence for an effect of the uterus on the ovary after parturition, whereby uterine bacteria have a contemporaneous localized effect on ovarian follicle selection and subsequent growth and function, but not on initial emergence.

scholarly journals Mathematical modelling of oxygen transport-limited follicle growth

Reproduction ◽  
2007 ◽  
Vol 133 (6) ◽  
pp. 1095-1106 ◽  
Author(s):  
G P Redding ◽  
J E Bronlund ◽  
A L Hart
Keyword(s):  
Mathematical Modelling ◽  
Oxygen Transport ◽  
Size Range ◽  
Ovarian Follicle ◽  
Antral Follicle ◽  
Follicle Growth ◽  
Preantral Follicles ◽  
Formation Stage ◽  
Ultimate Fate ◽  
Further Development

Mathematical modelling was used to investigate oxygen transport in the developing ovarian follicle. In contrast to previous findings, the results show that oxygen can reach the oocyte in large preantral follicles. This is largely due to the inclusion of fluid voidage in the model and improved estimates of oxygen diffusion coefficients through the granulosa. The results also demonstrate that preantral follicles will eventually reach a size beyond which further growth will result in the follicle becoming increasingly anoxic. The predicted size range at which this occurs is consistent with the size range at which antrum formation is observed in many mammals. This suggests that the antrum formation stage of follicular growth may be pivotal to the further development and ultimate fate of the follicle, and that antrum formation itself may represent a mechanism by which the follicle can overcome oxygen limitations. This was supported through extension of the model to the antral follicle, which showed that antrum formation can provide a way in which the follicle can continue to grow and yet avoid becoming hypoxic. The results of the model were consistent with observed follicle development.

scholarly journals Anti-Müllerian hormone and polycystic ovary syndrome: a mountain too high?

Reproduction ◽  
2010 ◽  
Vol 139 (5) ◽  
pp. 825-833 ◽  
Author(s):  
Laura Pellatt ◽  
Suman Rice ◽  
Helen D Mason
Keyword(s):  
Polycystic Ovary Syndrome ◽  
Polycystic Ovary ◽  
Primordial Follicle ◽  
Serum Levels ◽  
Dominant Follicle ◽  
Ovary Syndrome ◽  
Inhibitory Role ◽  
Mullerian Ducts ◽  
Human Ovaries ◽  
Follicle Selection

Anti-Müllerian hormone (AMH) was initially thought to be produced solely by the foetal male during sexual differentiation to promote regression of the Müllerian ducts. Over the last decade, however, a new and interesting role has emerged for AMH in the ovary. In human ovaries, AMH is produced by granulosa cells from 36 weeks of gestation until menopause, with the highest expression being in small antral follicles. AMH production gradually declines as follicles grow; once follicles reach a size at which they are dominant, it has largely disappeared. Its removal from these larger follicles appears to be an important requirement for dominant follicle selection and progression to ovulation as AMH has an inhibitory role in the ovary, reducing both primordial follicle initiation and follicle sensitivity to FSH by inhibition of aromatase. It is for this reason that AMH is a focus of interest in polycystic ovary syndrome (PCOS). Serum levels are doubled, and granulosa cell production is greatly increased. Interestingly, there appear to be two groups of women with PCOS who can be distinguished by their AMH level: one group consists of those who have high levels which do not reduce with treatment and who respond less well to induction of ovulation, and a second group consists of those in whom the level is less elevated and reduces on treatment and who seem to respond rather better. Understanding the reason for the raised AMH in PCOS may give clues as to the mechanism of anovulation. To conclude, AMH appears to have a major inhibitory role during folliculogenesis, which may contribute to anovulation in PCOS.

129 Ovarian dynamics and gonadotropins during selection of the dominant follicle in postpartum lactating versus non-postpartum cycling mares

2020 ◽  
Vol 32 (2) ◽  
pp. 191
Author(s):  
M. Pastorello ◽  
M. O. Gastal ◽  
G. K. Piquini ◽  
D. B. Godoi ◽  
E. L. Gastal
Keyword(s):  
Growth Rate ◽  
Maximum Diameter ◽  
Sequential Data ◽  
Dominant Follicle ◽  
Follicle Diameter ◽  
The Mean ◽  
Low Levels ◽  
Follicle Selection ◽  
Ovarian Dynamics ◽  
Selection Of

The mare, compared to other livestock, has the shortest interval from partum to the first ovulation. In monovulatory species, the follicle deviation process in a wave is characterised by the continued growth of the dominant follicle (DF) and regression of the subordinate follicle. Although follicle diameter deviation, a key event of follicle selection, has been investigated during the oestrous and menstrual cycles, the occurrence of this phenomenon before the first postpartum ovulation seems to be unclear in all species. This study aimed to compare the follicular dynamics and gonadotropin profiles around the follicle diameter deviation day in postpartum lactating (PP Lactating; n=24) versus non-postpartum cycling (NPP Cycling; n=15) mares. On the day of parturition, every PP Lactating mare was paired with an NPP Cycling mare, and ovarian follicles (&gt;4mm) were tracked daily by transrectal ultrasonography, and blood samples were collected. Data were analysed in the PP Lactating group according to the length of the partum-ovulation interval (POI; ≤22 and &gt;22 days) and the postpartum interovulatory interval (PPIOI), and in the NPP Cycling group during two interovulatory intervals (1st and 2nd IOI). In addition, regardless of group, all four intervals were compared. We performed the FSH and LH assays using radioimmunoassay. Ovarian and hormonal parameters were analysed using ANOVA for sequential data. The day and diameter of the DF at the deviation (overall mean: 14.9±2.5 days; 21.7±0.4mm, respectively) were not different (P&gt;0.05) between PP Lactating and NPP Cycling mares. However, when considering the length of POI, follicle deviation occurred 4.4±0.8 days earlier (P&lt;0.001) in mares with POI ≤ 22 days than in mares with POI&gt;22 days. No difference was found between PP Lactating and NPP Cycling mares within and between groups for the intervals from deviation to maximum diameter of the DF (10.4±0.4 days), for the intervals from deviation to ovulation (12.1±0.5 days), or for the growth rates of the DF from deviation to maximum diameter (2.6±0.1mm per day). The growth rate of the DF from deviation to ovulation (2.4±0.1mm per day) did not differ between PP Lactating and NNP Cycling mares; however, this growth rate was lower (P&lt;0.03) in the POI, PPIOI, and 1st IOI compared with the 2nd IOI. The mean diameter of the DF around deviation (days −3 to 3; 22.5±0.3mm), and systemic FSH (days −4 to 4; 10.3±0.2ngmL−1) were not different between PP Lactating and NPP Cycling mares. Level of LH was lower (P&lt;0.0001) around deviation (days −4 to 4) in the PP Lactating (0.7±0.0ngmL−1) versus the NPP Cycling mares (1.8±0.1ngmL−1). Results demonstrated that a partum effect occurs only on the day of deviation in mares during the foal heat (POI ≤ 22 days) and that low levels of LH during both intervals in PP Lactating mares were not detrimental to prevent ovulation.

Antifolliculogenic action of progesterone despite hypersecretion of FSH in monkeys

1982 ◽  
Vol 243 (5) ◽  
pp. E387-E397 ◽  
Author(s):  
A. L. Goodman ◽  
G. D. Hodgen
Keyword(s):  
Luteinizing Hormone ◽  
Luteal Phase ◽  
Functional Role ◽  
Follicle Stimulating Hormone ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Lh Surge ◽  
The Face ◽  
Peripheral Conversion ◽  
Midluteal Phase

To learn how progesterone (P) inhibits follicle growth during the luteal phase, we determined whether P will inhibit follicle growth when follicle-stimulating hormone (FSH) is secreted in large amounts, namely, after luteectomy (CLX) in monkeys with only one ovary. Second, a functional role for 17 alpha-hydroxyprogesterone (17OHP) was examined as a common mediator of the inhibition of folliculogenesis by the dominant follicle and corpus luteum. To accomplish the first goal, nine chronically hemiovarectomized monkeys were lutectomized chronically hemiovariectomized monkeys were luteectomized at midluteal phase. In five monkeys that received no steroid, the next preovulatory luteinizing hormone (LH) surge occurred 14.0 +/- 0.8 days (mean +/- SE) after CLX. In contrast, the next LH surge was delayed in four monkeys implanted for 10 days with Silastic capsules containing P and occurred 25.0 +/- 2.7 days after CLX, i.e., 14.8 +/- 2.7 days after the capsule removal. In both groups, FSH levels increased markedly after CLX to a comparable degree and duration; yet, only a single follicle ovulated in each monkey. To examine a potential inhibitory role for 17OHP, monkeys with two ovaries were luteectomized and received 1) no steroid, 2) 17OHP via Silastic capsules, or 3) P for 10 days after CLX. Progesterone replacement after CLX appeared to maintain 17OHP levels, which showed a transient decrease after CLX alone. As above, P delayed the next LH surge (25.4 +/- 1.3 vs. 15.0 +/- 0.6 days) despite comparable increases in serum FSH after CLX alone. Replacement at two levels of 17OHP did not delay the onset of menses (2-3 days post-CLX) or significantly delay the next LH surge 18.3 +/!- 1.9 or 20.8 +/- 3.4 vs. 15.0 +/- 0.6 days (P greater than 0.2) in monkeys CLX only. Whatever may be the mode of action of P, it appears that it is not mediated by peripheral conversion to 17OHP. These findings demonstrate that P at luteal phase levels can inhibit follicle growth culminating in ovulation even in the face of sustained, elevated levels of endogenous FSH. Because single ovulations occurred despite unambiguous and prolonged increments in serum FSH after CLX, the precise regulation of the ovulatory quota in this primate appears to be accomplished by means other than FSH alone.

Follicle dominance and ovarian asymmetry after luteectomy in rhesus monkeys

1982 ◽  
Vol 243 (4) ◽  
pp. E325-E331 ◽  
Author(s):  
A. L. Goodman ◽  
M. J. Koering ◽  
W. E. Nixon ◽  
R. F. Williams ◽  
G. D. Hodgen
Keyword(s):  
Rhesus Monkeys ◽  
Selection Process ◽  
Ovarian Cycle ◽  
Ovarian Activity ◽  
Dominant Follicle ◽  
Lh Surge ◽  
Morphological Asymmetry ◽  
Cynomolgus Macaques ◽  
Follicle Selection ◽  
Midluteal Phase

Previous work demonstrated that asymmetrical ovarian activity accompanies morphological asymmetry during the ovarian cycle in rhesus and cynomolgus macaques. This study was designed to determine whether functional ovarian asymmetry could be used to detect the upcoming dominant follicle (DF) even before it was grossly visible. Revealing a latent DF in this manner would permit a better estimate of the time when dominance of the follicle selected to ovulate is attained. To accomplish this, rhesus monkeys were luteectomized at midluteal phase to synchronize subsequent follicle growth, and 4 or 8 days later either the ipsilateral or contralateral ovary was removed. Unilateral ablation at day 4 (when no DF is grossly apparent) of either ovary produced symmetrical responses: the interval from luteectomy (CLX) to the next luteinizing hormone (LH) surge was extended by about 4 days in both groups (P less than 0.01), i.e., from about 12.5 days to 16.7 +/- 1.6 and 17.0 +/- 1.5 days (mean +/- SE). In contrast, hemiovariectomy at day 8 produced markedly divergent asymmetrical responses. Removal of the ipsilateral ovary 8 days after CLX did not affect the timing of the next LH surge (13.2 +/- 0.6 days), which ordinarily occurs about 12.5 days after CLX alone. However, ablation of the contralateral ovary (bearing the next DF) on day 8 extended the interval from CLX to the next LH surge from about 12.5 to 26.6 +/- 1.3 days. These findings indicate that, during the normal ovarian cycle when menses occurs 2--4 days after luteolysis, the follicle destined to ovulate becomes dominant between the 2nd and 6th day and that attainment of dominance signals the completion of a follicle selection process that begins or resumes promptly after luteolysis.

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