scholarly journals Peripheral concentrations of inhibin A, ovarian steroids, and gonadotropins associated with follicular development throughout the estrous cycle of the sow

Reproduction ◽  
2010 ◽  
Vol 139 (1) ◽  
pp. 153-161 ◽  
Author(s):  
Michiko Noguchi ◽  
Koji Yoshioka ◽  
Seigo Itoh ◽  
Chie Suzuki ◽  
Sachiko Arai ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Luteal Phase ◽  
Inverse Relationship ◽  
Plasma Concentrations ◽  
Follicular Development ◽  
Follicular Phase ◽  
Follicular Growth ◽  
Inhibin A ◽  
Ovarian Steroids ◽  
Feedback Regulator

We investigated changes in peripheral concentrations of inhibin A, total inhibin, steroids, and gonadotropins throughout the intact estrous cycle of the sow in relation to ovarian changes determined by daily transrectal ultrasonography. All visible follicles of 3 mm or more in diameter were classified as small (≥3 and <6 mm) or large (≥6 mm). Follicular recruitment was identified in two periods of the cycle: one from the late luteal to the follicular phase, characterized by an increase in the number of small follicles followed by the appearance of large follicles; and another during the early luteal phase, consisting only of increased numbers of small follicles. Plasma concentrations of inhibin A increased (P<0.05), coinciding with the two periods of follicle emergence. Estradiol (E2) levels increased (P<0.05) during the follicular phase, but not during the early luteal phase. An inverse relationship (P<0.01) between the patterns of inhibin and FSH concentrations was noted around the two periods of follicle emergence, but there was no relationship (P≥0.1) between the patterns of plasma E2and FSH during the early luteal phase. In conclusion, measurement of plasma inhibin A levels combined with ultrasonographic examination of the ovaries revealed two periods of synchronous follicular growth during the sow's estrous cycle. The results strongly suggest that inhibin A functions as a negative feedback regulator of FSH secretion throughout the estrous cycle, whereas E2appears to influence FSH secretion only during the follicular phase.

1 PROGESTERONE AS THE DRIVING REGULATORY FORCE BEHIND SERUM FSH CONCENTRATIONS AND ANTRAL FOLLICULAR GROWTH IN CYCLIC EWES

2010 ◽  
Vol 22 (1) ◽  
pp. 159
Author(s):  
T. E. Baby ◽  
P. M. Bartlewski
Keyword(s):  
Treatment Group ◽  
Estrous Cycle ◽  
Luteal Phase ◽  
Follicular Development ◽  
Serum Levels ◽  
Time Frame ◽  
Corpora Lutea ◽  
Research Station ◽  
Follicular Growth ◽  
Follicular Waves

Ovarian antral follicles in sheep grow in an orderly succession, producing typically 3 to 4 follicular waves per 17-day estrous cycle. Each wave is preceded by a transient increase in circulating FSH concentrations. The mechanism controlling the number of recurrent FSH peaks and emerging follicular waves remains unknown. During the ewe's estrous cycle, the time between the first 2 FSH peaks and days of wave emergence is longer than the intervals separating the ensuing FSH peaks and follicular waves. The prolonged inter-peak/inter-wave interval occurs early in the luteal phase when low levels of progesterone are secreted by developing, or non-fully functional, corpora lutea. The purpose of the present study was to determine the effect of varying progesterone (P4) levels on circulating concentrations of FSH and antral follicular development in sheep. Exogenous P4 (15 mg per ewe i.m.) was administered twice daily to 6 cycling Rideau Arcott × Dorset ewes from Day 0 (ovulation) to Day 4 (the mean duration of the inter-wave interval); 6 animals served as controls. Follicular growth was monitored in all animals by daily transrectal ultrasonography (Days 0 to 9). Jugular blood samples were drawn twice a day from Day 0 to 4 and then daily until Day 9 to measure systemic concentrations of P4 and FSH. The first FSH peak post-ovulation was detected on Day 1.4 ± 0.2 and 4.0 ± 0.2 in treated and control ewes, respectively (P < 0.05). The next FSH peak(s) occurred on Days 3.4 ± 0.3 and 5.2 ± 0.2 in the treatment group and on Day 5.5 ± 0.3 in controls. Consequently, the treatment group had, on average, 3 follicular waves emerging on Days 0, 3, and 6, whereas the controls produced 2 waves emerging on Days 0 and 5 (P < 0.05).We then retrospectively analyzed and compared daily serum concentrations of P4 and FSH obtained in cyclic Western White Face ewes (Columbia × Rambouillet) that had 3 (n = 10) or 4 (n = 19) follicular waves per cycle. Mean P4 concentrations were greater (P < 0.05) in sheep with 4 waves per cycle compared with their counterparts, which had 3 waves of follicular growth. Interestingly, the ewes with 3 waves exceeded (P < 0.05) all animals with 4 follicular waves in mean serum FSH concentrations on Days 0 to 2, 6 to 7, and 9 to 15 post-ovulation. In summary, creation of mid-luteal phase levels of P4 in metestrus shortened the time to the first post-ovulatory FSH peak in ewes, resulting in emergence of one more follicular wave compared with control animals during the same time frame. The ewes exhibiting 4 waves of follicular emergence had greater serum levels of P4 but lower FSH concentrations compared with sheep with 3 waves per cycle. Therefore, progesterone appears to be a key endocrine signal governing the control of periodic increases in serum FSH concentrations and the number of follicular waves in cyclic sheep. This study was funded by OMAFRA and NSERC grants. Appreciation is extended to Norman C. Rawlings, Susan Cook, and Sekallu Srinivas (University of Saskatchewan) and the staff at Ponsonby Sheep Research Station.

Plasma Concentrations of Ir-inhibin, Inhibin A, Inhibin pro-αC, FSH, and Estradiol-17β During Estrous Cycle in Mares and Their Relationship with Follicular Growth

Endocrine ◽  
2004 ◽  
Vol 25 (1) ◽  
pp. 07-14 ◽  
Author(s):  
Mohamed S. Medan ◽  
Yasuo Nambo ◽  
Natsuko Nagamine ◽  
Hiromi Shinbo ◽  
Gen Watanabe ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Plasma Concentrations ◽  
Follicular Growth ◽  
Inhibin A ◽  
Estradiol 17Β

scholarly journals Follicular waves and concentrations of steroids and inhibin A in ovarian venous blood during the luteal phase of the oestrous cycle in ewes with an ovarian autotransplant

1998 ◽  
Vol 156 (3) ◽  
pp. 563-572 ◽  
Author(s):  
CJ Souza ◽  
BK Campbell ◽  
DT Baird
Keyword(s):  
Luteal Phase ◽  
Venous Blood ◽  
Follicular Development ◽  
Inhibin A ◽  
Ovarian Steroids ◽  
Antral Follicles ◽  
Follicular Wave ◽  
Follicle Diameter ◽  
Before And After ◽  
Follicular Size

The dynamics of ovarian follicular development and the pattern of pituitary and ovarian hormone concentration were investigated during the luteal phase in ewes with autotransplanted ovaries. The follicles were measured by ultrasound and samples of ovarian and jugular venous blood were collected at intervals of 12 h. Blood samples were collected before and after a GnRH challenge (250 ng GnRH, i.v.) to allow the determination of basal and LH-stimulated concentration of ovarian steroids. Throughout the luteal phase, large antral follicles developed in three waves, each of which was preceded by a rise in the concentration of FSH (P < 0.05). The concentrations of oestradiol and androstenedione in the unstimulated and LH-stimulated samples were similar (P > 0.05) during the first 3 days of the luteal phase but differed thereafter, with the LH-stimulated being significantly higher than the basal concentrations (P < 0.05). In the first wave of follicular development the changes in follicular size were accompanied by an increase in the concentration of ovarian steroids and inhibin A. During the second follicular wave, although changes in follicle diameter were similar to the first wave (P > 0.05), the basal concentration of ovarian steroids and inhibin A remained unchanged throughout the period of emergence and demise of the large follicles. These results confirm that the development of large antral follicles during the luteal phase of the sheep occurs in successive waves that are associated with fluctuations in FSH secretion. However while the results strongly suggest that fluctuations in both inhibin A and oestradiol secretion control FSH during the first follicular wave, the cause of the FSH fluctuations associated with waves two and three is unclear. Final resolution of this issue may need to await the development of a specific assay for dimeric inhibin B.

scholarly journals CYTOMORPHOLOGICAL RESEARCH OTSYT-CUMULUS COMPLEXES RABBIT FROM WITH OVARIAN AT DIFFERENT STAGES OF THE ESTROUS CYCLE

2017 ◽  
Vol 53 ◽  
pp. 279-284
Author(s):  
A. B. Zyuzyun
Keyword(s):  
Estrous Cycle ◽  
Luteal Phase ◽  
Follicular Phase ◽  
The Body ◽  
Follicular Growth ◽  
Research Results ◽  
Significant Difference ◽  
Further Development ◽  
Ovarian Follicular Growth

The analysis of the research results revealed that the largest number (86.4%) of oocytes suitable for further development outside the body can be obtained with ovarian follicular phase of growth. It should be noted that statistically significant difference was observed between the groups OCC rabbit derived from ovaries at different phases of the estrous cycle by the number oocytes unsuitable for further cultivation. Thus, the phase of the ovarian follicular growth of gametes was obtained only 13.6% of ovarian and with signs of ovulation and the luteal phase, 35.4% and 31.4% respectively. When comparing the results of the analysis of cytogenetic preparations oocytes from ovaries removed rabbit at different stages of the estrous cycle, found that regardless of the phase of the estrous cycle Yachnik mostly larger number of oocytes were under dyploteny. The largest number of gametes with diffuse chromatin at the stage dyploteny (37.3%) received from the stage ovarian follicular growth. At the stage of fibrillar dyploteny increasing number of gametes was removed from ovarian luteal phase of the estrous cycle. In step dyploteny visible bivalent were more likely gametes obtained from stage ovarian follicular growth (18,1%, p <0,05). The highest percentage of oocytes degeneration chromatin was observed in the group removed from the ovaries to the rabbit lyutealniy phase (21.6%).

scholarly journals Regulation of the hyaluronan system in ovine endometrium by ovarian steroids

Reproduction ◽  
2013 ◽  
Vol 145 (5) ◽  
pp. 491-504 ◽  
Author(s):  
Kabir A Raheem ◽  
Waleed F Marei ◽  
Karen Mifsud ◽  
Muhammad Khalid ◽  
D Claire Wathes ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Protein Expression ◽  
Mrna Expression ◽  
Differential Expression ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Steroid Treatment ◽  
Ovarian Steroids ◽  
Protein Levels ◽  
Steroid Regulation

In this study, we investigated steroid regulation of the hyaluronan (HA) system in ovine endometrium including HA synthases (HAS), hyaluronidases, and HA receptor-CD44 using 30 adult Welsh Mountain ewes. Eight ewes were kept intact and synchronized to estrous (day 0). Intact ewes were killed on day 9 (luteal phase; LUT; n=5) and day 16 (follicular phase; FOL; n=3). The remaining ewes (n=22) were ovariectomized and then treated (i.m.) with vehicle (n=6) or progesterone (n=8) for 10 days, or estrogen and progesterone for 3 days followed by 7 days of progesterone alone (n=8). Estradiol and progesterone concentrations in plasma correlated with the stage of estrous or steroid treatment. Our results showed trends (P<0.1) and statistically significant effects (P<0.05, by t-test) indicating that LUT had lower HAS1 and HAS2 and higher HAS3 and CD44 mRNA expression compared with FOL. This was reflected in immunostaining of the corresponding HAS proteins. Similarly, in ovariectomized ewes, progesterone decreased HAS1 and HAS2 and increased HAS3 and CD44, whereas estradiol tended to increase HAS2 and decrease CD44. Sometimes, HAS mRNA expression did not follow the same trend observed in the intact animals or the protein expression. HA and its associated genes and receptors were regulated by the steroids. In conclusion, these results show that the level of HA production and the molecular weight of HA in the endometrium are regulated by ovarian steroids through differential expression of different HAS both at the gene and at the protein levels.

scholarly journals Secretion of inhibin A, inhibin B and inhibin pro-alphaC during the oestrous cycle of the golden hamster (Mesocricetus auratus)

1999 ◽  
Vol 162 (3) ◽  
pp. 451-456 ◽  
Author(s):  
K Ohshima ◽  
H Kishi ◽  
M Itoh ◽  
G Watanabe ◽  
K Arai ◽  
...  
Keyword(s):  
Golden Hamster ◽  
Plasma Concentrations ◽  
Follicular Development ◽  
Early Morning ◽  
Oestrous Cycle ◽  
Inhibin B ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inhibin A ◽  
Negative Relationships ◽  
Plasma Oestradiol

Plasma concentrations of inhibin pro-alphaC, inhibin A and inhibin B were determined by enzyme-linked immunosorbent assay at 6 h intervals throughout the 4-day oestrous cycle of the golden hamster. Plasma concentrations of follicle-stimulating hormone (FSH) and oestradiol-17beta were also measured by radioimmunoassay during the oestrous cycle. Plasma concentrations of inhibin A increased from the early morning of day 1 (day 1=day of ovulation) and reached plateau levels at 0500 h on day 2. An abrupt increase in plasma concentrations of inhibin A was found at 1700 h on day 4, when the preovulatory FSH surge was observed. An increase in plasma concentrations of inhibin B occurred on day 1 and reached plateau levels at 1700 h on day 1. The levels remained elevated until 0500 h on day 4 and declined gradually by 2300 h on day 4. Plasma concentrations of inhibin pro-alphaC gradually increased with some fluctuation from day 1 to 1700 h on day 4 and then declined. Significant negative relationships were noted between plasma FSH and both dimeric forms of inhibin from day 1 to day 3. Significant positive relationships were found between plasma oestradiol-17beta and inhibin A or inhibin pro-alphaC throughout the oestrous cycle. In contrast, no significant relationship was found between plasma oestradiol-17beta and inhibin B. These findings suggest that both dimeric forms of inhibin play a role in the regulation of FSH secretion during follicular development. These findings also suggest that inhibin pro-alphaC could be secreted primarily by large follicles, and early atretic follicles could also be responsible for inhibin pro-alphaC secretion. On the other hand, the secretory pattern of dimeric inhibins might shift from inhibin B to inhibin A with follicular development.

Ovarian secretion rates and peripheral concentrations of inhibin in normal and androstenedione-immune ewes with an autotransplanted ovary

1990 ◽  
Vol 127 (2) ◽  
pp. 285-296 ◽  
Author(s):  
B. K. Campbell ◽  
D. T. Baird ◽  
A. S. McNeilly ◽  
R. J. Scaramuzzi
Keyword(s):  
Luteal Phase ◽  
Venous Blood ◽  
Plasma Concentrations ◽  
Active Immunization ◽  
Follicular Phase ◽  
Secretion Rate ◽  
Luteal Function ◽  
Prostaglandin F ◽  
Ovarian Inhibin ◽  
Secretion Rates

ABSTRACT Active immunization of sheep against androstenedione results in an increase in ovulation rate that is associated with increased plasma levels of LH and progesterone, but not FSH. Although immunized ewes have more activated follicles the secretion rate of oestradiol is not increased. An experiment was conducted to examine the effect of androstenedione immunity on the ovarian secretion and peripheral plasma concentrations of inhibin. Merino ewes in which the left ovary had been autotransplanted to a site in the neck were divided into control (n = 5) and androstenedione-immune (n = 6) groups. Ovarian and jugular venous blood was collected every 10 min at two stages of the follicular phase, 21–27 h and 38–42 h after a luteolytic dose of an analogue of prostaglandin F2α (PG), and every 15 min for 6 h on day 10 of the subsequent luteal phase. The ewes were monitored regularly for luteal function by measurement of the concentration of progesterone and preovulatory LH surges. The concentration of inhibin in jugular and ovarian venous plasma was determined by radioimmunoassay and ovarian secretion rates and peripheral concentrations are expressed as pg of 1–26 peptide fragment of the α chain. The ovarian secretion rate of inhibin tended to be greater in androstenedione-immune ewes at all stages of the oestrous cycle measured, with this difference being statistically significant (P <0·05) during the luteal phase (100±40 and 260±80 (s.e.m.) pg/min for control and immune groups respectively). The pattern of ovarian inhibin secretion exhibited pulsatile-like fluctuations which were not associated with LH pulses. Peripheral concentrations of inhibin were generally higher in immunized than in control ewes with this difference being significant (P < 0·01) from day 4 to 14 of the luteal phase (59±5 and 110±7 ng/1 for control and immune respectively). The ovarian secretion rate of immunoactive inhibin was greater (P <0·01) during the follicular phase than during the luteal phase in both groups of ewes, and peripheral concentrations of inhibin increased (P < 0·001) following injection of PG in ewes from both treatment groups. We concluded that androstenedione immunity results in an increase in ovarian inhibin secretion, an effect that can probably be attributed to the greater number of large oestrogenic follicles present in the ovaries of these ewes. Furthermore, this increase in the concentration of inhibin may override any decrease in the negative feedback effects of ovarian steroid produced by immunization and, hence, explain the paradoxical findings of normal concentrations of FSH and raised concentrations of LH in ewes which are immunized against androstenedione. Journal of Endocrinology (1990) 127, 285–296

Effects of immunization against recombinant bovine inhibin α subunit on circulating concentrations of gonadotrophins in ewes

1989 ◽  
Vol 120 (1) ◽  
pp. 59-65 ◽  
Author(s):  
J. K. Findlay ◽  
B. Doughton ◽  
D. M. Robertson ◽  
R. G. Forage
Keyword(s):  
Breeding Season ◽  
Untreated Control ◽  
Luteal Phase ◽  
Plasma Concentrations ◽  
Follicular Phase ◽  
Ovulation Rate ◽  
Α Subunit ◽  
Keyhole Limpet Haemocyanin ◽  
Fourfold Increase ◽  
Breeding Seasons

ABSTRACT Immunization of ewes against a pure recombinant preparation of the α subunit of bovine inhibin (α-bI) resulted in a three- to fourfold increase in ovulation rate, associated with antibodies in plasma recognizing pure native 31 kDa inhibin. The aim of this study was to examine the effects of this immunization on basal and GnRH-stimulated plasma concentrations of FSH and LH in ewes during the anoestrous and breeding seasons. The groups were untreated control ewes (n = 5), control ewes treated with keyhole limpet haemocyanin (KLH alone, n = 4), ewes treated with α-bI alone (n = 4) and α-bI–KLH conjugate-treated ewes (n = 3). There were no effects of immunization on basal FSH or LH in anoestrous ewes, despite the presence of antibodies recognizing 31 kDa inhibin. In the breeding season, immunization against α-bI resulted in increased basal (follicular phase, P < 0·1; luteal phase P < 0·05) and GnRH-stimulated (follicular phase only, P < 0·001) release of FSH, but not LH. The data are compatible with the hypotheses that the increase in ovulation rate in immunized ewes is due to an increase in circulating FSH concentrations and that inhibin may only have a major peripheral influence on FSH in sheep during the breeding season. Journal of Endocrinology (1989) 120, 59–65

Changes in the Dopaminergic Control of Prolactin Secretion and in Ovarian Steroids in Migraine

Cephalalgia ◽  
1986 ◽  
Vol 6 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Giovanni Murialdo ◽  
Emilia Martignoni ◽  
Andrea De Maria ◽  
Maria Luisa Bonura ◽  
Grazia Sances ◽  
...  
Keyword(s):  
Luteal Phase ◽  
Healthy Subjects ◽  
Inhibitory Effect ◽  
Prolactin Secretion ◽  
Follicular Phase ◽  
Ovarian Steroids ◽  
Da Receptors ◽  
Dopaminergic Supersensitivity ◽  
Responses To Dopamine ◽  
Dopaminergic Control

Prolactin (PRL) responses to dopamine (DA) blockers and to direct and indirect DA agonists have been studied in 23 healthy women, 17 women with catamenial migraine and 17 with non-catamenial migraine in both their follicular and luteal phases. PRL responses to the DA blockers were greater in the follicular phase of both migraine groups than in controls. The inhibitory effect of nomifensine on PRL secretion was dampened in the follicular phase of both migraine groups. These findings demonstrate an increased PRL reserve in migraine and suggest the existence of a dopaminergic supersensitivity of the lactotrophic postsynaptic DA receptors. The impaired inhibitory effect of nomifensine on PRL secretion hints at a decrease of the presynaptic DA content in tuberoinfundibular DA neurons. In migrainous women 17-β-oestradiol levels are higher in both ovarian phases, whereas progesterone concentrations and the progesterone to oestradiol ratio are lower than in healthy subjects in the luteal phase. These data suggest the existence of a change in the oestrogen-dependent modulation of pituitary DA receptors.

Follicular waves are associated with transient fluctuations in FSH but not oestradiol or inhibin-A concentrations in anoestrous ewes

2001 ◽  
Vol 72 (3) ◽  
pp. 547-554 ◽  
Author(s):  
A.C.O. Evans ◽  
P. Duffy ◽  
K. M. Quinn ◽  
P. G. Knight ◽  
M. P. Boland
Keyword(s):  
Breeding Season ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Transrectal Ultrasonography ◽  
Ultrasound Scanning ◽  
Follicular Growth ◽  
Inhibin A ◽  
Blood Samples ◽  
Follicular Waves

AbstractThe aim was to examine statistically the changes among days in the numbers of follicles relative to the growth of large follicles to test the hypothesis that follicular development occurs in a wave-like fashion in anoestrous ewes. The relationships among the patterns of circulating concentrations of FSH, oestradiol and inhibin-A and the pattern of follicular growth as well as relationships among follicular fluid steroid and inhibin-A concentrations were also studied. The ovaries of 11 ewes were examined daily using transrectal ultrasonography for 14 days and blood samples were collected every 8 h for 9 days. Five ewes were ovariectomized on the last day of ultrasound scanning. One to three identified follicles (a cohort) emerged every 2 to 5 days (mean 2·9 (s.e. 0·2) days) in individual ewes. The numbers of 4 and 5 mm follicles were fewest (P < 0·05) before and greatest (P < 0·05) 1 day after cohort emergence. This change in the numbers of follicles indicates a wave-like pattern of follicular growth. FSH concentrations were greatest (P < 0·05) on the day before wave emergence and lowest (P < 0·05) on the day of wave emergence. Peripheral concentrations of oestradiol and inhibin-A did not fluctuate (P > 0·05) in association with the emergence of follicular waves. The follicles that were collected at ovariectomy originated from one of three different waves. Oestradiol and inhibin-A concentrations in follicular fluid and the oestradiol-to-progesterone ratio were not different among the largest follicles of successive waves, when follicles were collected at the same time, indicating that new waves of follicles developed before the demise of old waves.In conclusion, waves of follicles emerged about every 3 days in anoestrous ewes (defined as significant changes in numbers of follicles) and were associated with fluctuations in FSH concentrations but not peripheral oestradiol or inhibin-A concentrations. New follicular waves also emerged in the presence of steroidogenically active (positive oestradiol-to-progesterone ratio), inhibin-A producing follicles from a previous wave suggesting that follicles do not exert functional dominance during the non-breeding season.

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