scholarly journals Hormonal mechanism of follicle deviation as indicated by major versus minor follicular waves during the transition into the anovulatory season in mares

Reproduction ◽  
2003 ◽  
pp. 653-660 ◽  
Author(s):  
OJ Ginther ◽  
BG Woods ◽  
C Meira ◽  
MA Beg ◽  
DR Bergfelt
Keyword(s):  
Dominant Follicle ◽  
Follicle Growth ◽  
Follicular Waves ◽  
Hormonal Mechanism ◽  
A Minor ◽  
Temporal Basis

Follicle growth and circulating hormone concentrations were compared between an interovulatory interval and the first 60 days of the anovulatory season in pony mares. Daily observations were made from November of three groups: (i) ablation of follicles of >/=6 mm in diameter at day 10 after an ovulation that initiated an interovulatory interval, as determined retrospectively (ovulatory group, n=8), (ii) ablation at day 10 after the last ovulation of the year (anovulatory-10 group, n=6); and (iii) ablation at day 60 after the last ovulation of the year (anovulatory-60 group, n=6). Follicular waves were defined as major (dominant follicle) and minor (no dominant follicle). The percentage of mares with major waves after ablation for the ovulatory, anovulatory-10 and anovulatory-60 groups was 100, 33 and 0%, respectively, and the percentage with minor waves was 0, 67 and 100%, respectively. Minor waves were also detected in 83% of anovulatory mares between day 20 and day 60. Growth of the largest follicle was similar for major waves and minor waves but only until the beginning of deviation in the major waves. FSH surges after ablation were similar for all groups and for surges detected during days 20-60. Concentrations of LH were greater in association with major waves than with minor waves. Both diameter of the largest follicle and LH concentrations for minor waves were greater after ablation at day 10 after the last ovulation of the year than after ablation at day 60. The results of this study indicate that major follicular waves developed in some mares early in the anovulatory season and that minor waves developed throughout the first 2 months. Despite similarities in the wave-stimulating FSH surge, differences in follicle growth occurred and were attributable, on a temporal basis, to differences in LH concentrations. A minor wave developed into a major wave when the largest follicle reached a diameter characteristic of the beginning of deviation in the presence of an adequate LH stimulus for continued growth of a dominant follicle.

scholarly journals Follicular waves and circulating concentrations of gonadotrophins, inhibin and oestradiol during the anovulatory season in mares

Reproduction ◽  
2002 ◽  
pp. 875-885 ◽  
Author(s):  
FX Donadeu ◽  
OJ Ginther
Keyword(s):  
Blood Sample ◽  
Transitional Period ◽  
Follicle Growth ◽  
Follicular Waves ◽  
Follicular Wave ◽  
Mean Diameter ◽  
Concentration Changes ◽  
The Mean ◽  
Temporal Basis ◽  
Follicular Activity

Follicular waves and associated circulating hormone concentrations were studied during the anovulatory season in pony mares (n=8). Follicles were monitored by ultrasonography and a blood sample was taken daily from 29 January until ovulation (mean, 28 April). A mid-anovulatory period (largest follicle, 16.0+/-0.5 mm in diameter) and transitional period (largest follicle, 22.4+/-0.5 mm) were distinctive in each mare. The two periods were delineated by an increase in the diameter of the largest follicle to >/=21.0 mm. Follicular waves, identified by significant increases in the mean diameter of the second to sixth largest follicles, were detected during both the mid-anovulatory and transitional periods. The mean number of follicles >/=15.0 mm in diameter and the diameter of the second to sixth largest follicles increased in association with statistically identified FSH surges. The pattern of the FSH concentration changes during surges did not change during the mid-anovulatory and transitional periods. During the declining portion of the FSH surge, follicle growth continued and circulating total inhibin increased, indicating suppression of FSH by inhibin from the growing follicles. Circulating oestradiol or LH did not change relative to wave emergence. Results indicated that follicular waves occurred during the second-half of the anovulatory season, even during the period of lowest follicular activity. On a temporal basis, follicular wave emergence was stimulated by surges in circulating FSH. However, the increase in follicle growth to >/=21.0 mm in diameter for the wave at the beginning of the transitional period and for the subsequent waves was not attributable to a change in the characteristics of the associated FSH surges.

scholarly journals Investigations on the vaginal temperature, cycle stages, and steroid hormone concentrations during the breeding season in camels (Camelus dromedarius)

2021 ◽  
pp. 1102-1108
Author(s):  
Ragab H. Mohamed ◽  
Amal M. Abo El-Maaty ◽  
Rasha S. Mohamed ◽  
Axel Wehrend ◽  
Fatma Ali ◽  
...  
Keyword(s):  
Temperature Cycle ◽  
Ovarian Activity ◽  
Dominant Follicle ◽  
Data Logger ◽  
Temperature Changes ◽  
Animal Reproduction ◽  
Follicular Waves ◽  
Release Device ◽  
Cyclic Changes ◽  
Vaginal Temperature

Background and Aim: Estrus detection plays a crucial role in the success of animal reproduction. It was previously reported that body temperature changes during estrus. This study aimed to investigate the relationship between vaginal temperatures (VTs) measured by a data logger, ovarian activity, and hormonal cyclic changes in camels. Materials and Methods: Six mature, healthy, non-pregnant dromedary, and 10-12-year-old camels were included in the study. The ovarian activity was monitored with ultrasonography, and estrus behavior was evaluated using an active and virile male camel. Animals were inserted with a blank controlled internal drug release device attached with an intravaginal data logger. Every hour, the ambient temperature was recorded by another data logger. Blood samples were collected, and sera were used to measure estradiol and progesterone levels. Results: The whole follicular cycle lasted 25.41±1.36 days, and the maximum sizes of the dominant follicle in the first and second follicular waves were 1.63±0.27 cm and 1.94±0.42 cm, respectively. There was a significant positive correlation between the follicular diameter and estradiol-17β level (p<0.01, r=0.397). There was no correlation between the follicular diameter and progesterone level (p>0.05, r=0.038), which remained low during the whole period of the experiment. The mean daily VT was significantly correlated with the diameter of the dominant follicle (1.7-2.2 cm, p<0.01, r=0.52). Conclusion: Measurement of VT will improve the accuracy of estrus prediction. Further studies are recommended to validate VT in camel reproduction.

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.

scholarly journals Organelle reorganization in bovine oocytes during dominant follicle growth and regression

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
D. Dadarwal ◽  
G. P. Adams ◽  
P. Hyttel ◽  
G. M. Brogliatti ◽  
S. Caldwell ◽  
...  
Keyword(s):  
Dominant Follicle ◽  
Follicle Growth ◽  
Bovine Oocytes

Effect of the dominant follicle on regression of its subordinates in heifers

1993 ◽  
Vol 73 (2) ◽  
pp. 267-275 ◽  
Author(s):  
G. P. Adams ◽  
K. Kot ◽  
C. A. Smith ◽  
O. J. Ginther
Keyword(s):  
Key Words ◽  
Maximum Diameter ◽  
Sham Operation ◽  
Dominant Follicle ◽  
Follicular Waves ◽  
Follicular Wave ◽  
The Relationship ◽  
Small Follicle

The relationship between a dominant follicle of a follicular wave and the suppression of subordinate follicles was studied during the first postovulatory wave (Wave 1) in Holstein heifers. The dominant follicle (largest follicle) was cauterized or a sham-operation was done on day 3 (day 0 = ovulation) using seven heifers per group. In the cautery group, compared to the controls, the largest subordinate follicle attained a larger diameter (11 7 vs 8 0 mm; P < 0.01), reached maximum diameter at a later day (day 9.2 vs. day 3.1; P < 0 01) and began to regress at a later day (day 14.3 vs. day 5.7; P < 0.01). In addition, the emergence of Wave 2 was hastened (day 6.4 vs. day 9.3; P < 0.05) and more heifers had more than two waves per interovulatory interval (5 of 6 vs. 2 of 7; P < 0.05). In heifers with the dominant follicle eliminated, the largest subordinate grew to the diameter of a dominant follicle during Wave 1 (n = 3) or became the dominant follicle of a newly emerged wave (n = 2). A subordinate sometimes persisted as a small follicle (e.g., 5 mm) for several days before resurging. However, it was not convincingly demonstrated that a subordinate follicle could resurge after it had begun to regress (decrease in diameter). Results supported the hypothesis that suppression of subordinate follicles is a prolonged process, so that resurgence of a subordinate can occur if the dominant follicle is removed. Key words: Ovaries, follicular waves, selection, cattle, cauterization

scholarly journals Clinical Applications of Ultrasound in Assessment of Follicle Development and Growth

2007 ◽  
Vol 1 (2) ◽  
pp. 50-63 ◽  
Author(s):  
V Vlaisavljevic ◽  
M Došen
Keyword(s):  
Blood Volume ◽  
Clinical Success ◽  
Clinical Applications ◽  
Follicular Phase ◽  
Growth Patterns ◽  
Follicle Development ◽  
Pulsed Doppler ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Late Follicular Phase

Abstract Monitoring of individual follicles during the menstrual cycle demonstrates in a noninvasive way the changes in their number and position during the early and the late follicular phase and the luteal phase. The differences in relations between the follicles near the dominant follicle can be demonstrated with the same technique using 3D reconstruction of the ovary. An increased perifollicular blood flow can be measured in the perifollicular period using color and pulsed Doppler. Automated estimation of blood volume around the ovarian follicles brought a new concept to this area. Results confirm the observation that vascularity around the follicle is intense in the periovulatory period. The blood volume does not differ between follicles containing an oocyte and those with no oocyte in the aspirate, or a nonfertilizable oocyte. From our results we can hypothesize that those follicles containing oocytes able to produce pregnancy have a more uniform perifollicular vascular network . Recognition of the follicle growth pattern has a prognostic value for the outcome of assisted reproduction methods. Follicular diameter and changes in growth patterns are more important than follicular wall thickness as parameters having an impact on clinical success.

177 EFFECTS OF MANIPULATION OF DOMINANT FOLLICLE GROWTH ON SIZE AND FUNCTION OF CORPUS LUTEUM IN BEEF CATTLE

2013 ◽  
Vol 25 (1) ◽  
pp. 237
Author(s):  
R. S. Ramos ◽  
F. S. Mesquita ◽  
G. Pugliesi ◽  
S. C. Scolari ◽  
M. L. Oliveira ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Corpus Luteum ◽  
Prostaglandin F2α ◽  
Progressive Increase ◽  
Group Effect ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Ovulatory Follicle ◽  
Conception Rates ◽  
And Function

Recent evidence indicates that the progesterone (P4) secretion by corpus luteum (CL) during early diestrus is affected by the size of ovulatory follicle and has a significant impact on embryo development and conception rates. Therefore, strategies to promote the growth of the dominant follicle and/or to stimulate the early development of the CL to increase P4 secretion become an alternative to improve conception rates in the beef cattle industry. Our aim was to study the effect of manipulations of the follicle growth on the diameter of the preovulatory follicle (POF) and subsequent size and function of the CL. Cyclic and non-lactating Nelore cows, pre-synchronized by 2 injections of prostaglandin F2α (PGF) 14 d apart, were manipulated to ovulate large or small follicles according to 3 experiments. In Experiment 1 (Exp. 1; n = 23), animals received a second-use intravaginal P4-releasing device along with an injection of oestradiol benzoate on Day –10 (Day 0 = GnRH injection). Cows were split to receive (large follicle group; LF) or not (small follicle group; SF) a PGF injection on Day –10. Progesterone devices were removed on Day –2.5 in the LF group and on Day –1.5 in the SF group. The PGF was injected at the removal of the P4 device. In Experiment 2 (Exp. 2; n = 38), cows in the LF group had the P4 device removed on Day –2.25 or Day –2, whereas in Experiment 3 (Exp. 3; n = 23), the device (first-use) was removed on Day –1.75 in the LF group and on Day –1.25 in the SF group; the other manipulations were similar to Exp. 1. Data analyses were done only on cows that had a functional CL on Day –10 (P4 > 1 ng mL–1) and that ovulated within 24 and 48 h post-GnRH (Exp. 1, n = 14; Exp. 2, n = 14; Exp. 3, n = 12). The three experiments were successful in inducing POF with different sizes, as indicated by the greater diameter of the POF in the LF group compared with SF in Exp. 1 (12.9 ± 0.5 mm v. 10.7 ± 0.6 mm; P < 0.03), Exp. 2 (14.1 ± 0.6 mm v. 11.7 ± 0.4 mm; P < 0.006), and Exp. 3 (13.8 ± 0.6 mm v. 11.7 ± 0.8 mm; P < 0.06). To evaluate the effect of POF size on size and function of the CL, a factorial analysis was performed by SAS software to test the effect of group, day, and their interaction. For CL volume, an effect of group was detected in Exp. 1 (P < 0.02) and in Exp. 3 (P < 0.06), but not in Exp. 2. The group effect represented greater average CL volume from Day 3 to Day 7 in LF (2.42 ± 0.27 and 2.5 ± 0.39 cm3) than in the SF group (1.39 ± 0.18 and 1.2 ± 0.15 cm3) for Exp. 1 and 3, respectively. For P4 concentrations, a group effect was detected only in Exp. 3 (P < 0.007), as indicated by greater average P4 concentrations from Day 3 to Day 7 in LF (2.31 ± 0.31 ng mL–1) than in the SF group (1.37 ± 0.19 ng mL–1). A day effect was detected in all experiments (P < 0.0001), as indicated by a progressive increase of CL volume and P4 concentrations from Day 3 to Day 7. Manipulation of follicle growth performed in Exp. 3 was the most efficient to modify the function and size of the CL. In conclusion, control of POF size by manipulation of P4 concentrations during growth of the dominant follicle alters the size and function of CL postovulation. CNPq, FAPESP, Ourofino, and PUSP-P.

The role of pregnenolone-metabolizing enzymes in the regulation of oestradiol biosynthesis during development of the first wave dominant follicle in the cow

1996 ◽  
Vol 149 (2) ◽  
pp. 233-242 ◽  
Author(s):  
P D Carrière ◽  
D Harvey ◽  
G M Cooke
Keyword(s):  
Follicular Fluid ◽  
Luteal Phase ◽  
Hydroxysteroid Dehydrogenase ◽  
Cytochrome P450 Enzyme ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Metabolizing Enzymes ◽  
P450 Enzyme ◽  
Rate Limiting

Abstract During the luteal phase in the cow, a first-wave dominant follicle grows to reach ovulatory size, but then ceases to grow, becomes no longer dominant and enters a phase of slow regression. During this growth transition, the concentration of oestradiol has been shown to decrease in follicular fluid. The objective of this study was to determine if follicular fluid oestradiol concentrations are regulated by the activity of three major steroidogenic enzymes, namely P450-aromatase (P450-arom), 3β-hydroxysteroid dehydrogenase/Δ5–Δ4 isomerase (3β-HSD) and 17α-hydroxylase C-17,20 lyase cytochrome P450 enzyme (P450–17α) measured in granulosa and theca cells isolated from individual first-wave dominant follicles. Follicle growth and state of dominance was assessed by ultrasonography and follicles were classified as growing-dominant (GD, n=6), non-growing-dominant (NGD, n=8) or non-growing-non-dominant (NGND, n=6). Mean follicular fluid concentrations of oestradiol were higher in GD than in NGD or NGND follicles (511 ± 98 versus 136 ± 16 and 20 ± 11 nmol/l respectively). Oestradiol was not correlated with P450-arom in any of the three groups. In GD follicles, oestradiol was positively correlated with pregnenolone concentration but neither was correlated with granulosa or theca 3β-HSD activity or with theca P450–17α activity. In NGD follicles, oestradiol was negatively correlated with theca 3β-HSD activity and pregnenolone was negatively correlated with granulosa 3β-HSD activity. In NGND follicles, oestradiol was positively correlated, and pregnenolone was negatively correlated with theca 3β-HSD and P450–17α activities. These studies demonstrated that pregnenolone supply is the principal regulating factor of oestradiol output during follicle dominance and during the loss of dominance but that the levels of P450–17α and 3β-HSD activity become rate-limiting when the follicle is no longer dominant. Journal of Endocrinology (1996) 149, 233–242

scholarly journals Lack of FSH support enhances LIF–STAT3 signaling in granulosa cells of atretic follicles in cattle

Reproduction ◽  
2015 ◽  
Vol 150 (4) ◽  
pp. 395-403 ◽  
Author(s):  
Gustavo Freitas Ilha ◽  
Monique T Rovani ◽  
Bernardo G Gasperin ◽  
Alfredo Quites Antoniazzi ◽  
Paulo Bayard Dias Gonçalves ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Transcript Abundance ◽  
Signalling Pathways ◽  
Molecular Characteristics ◽  
Dominant Follicle ◽  
Dominance Model ◽  
Follicular Waves ◽  
Stat3 Signaling ◽  
Interleukin 6 Receptor ◽  
Stat3 Signalling

Subordinate follicles (SFs) of bovine follicular waves undergo atresia due to declining FSH concentrations; however, the signalling mechanisms have not been fully deciphered. We used an FSH-induced co-dominance model to determine the effect of FSH on signalling pathways in granulosa cells of the second-largest follicles (SF in control cows and co-dominant follicle (co-DF2) in FSH-treated cows). The SF was smaller than DF in control cows while diameters of co-DF1 and co-DF2 in FSH-treated cows were similar. The presence of cleaved CASP3 protein confirmed that granulosa cells of SFs, but not of DFs and co-DFs, were apoptotic. To determine the effect of FSH on molecular characteristics of the second-largest follicles, we generated relative variables for the second largest follicle in each cow. For this, variables of SF or co-DF2 were divided by the variables of the largest follicle DF or co-DF1 in each cow. There was higher transcript abundance of MAPK1/3 and AKT1/2/3 but lower abundance of phosphorylated MAPK3/1 in SF than co-DF2 granulosa cells. Abundance of mRNA and phosphorylated protein of STAT3 was higher in granulosa cells of control SF than FSH-treated co-DF2. SF granulosa cells had higher levels of LIFR and IL6ST transcripts, the two receptors involved in STAT3 activation. Further, lower transcript abundance of interleukin 6 receptor (IL6R), another receptor involved in STAT3 activation, indicated that STAT3 activation in SF granulosa cells could be mainly due to leukemia inhibitory factor (LIF) signalling. These results indicate that atresia due to lack of FSH is associated with activated LIF–STAT3 signalling in SF granulosa cells, as FSH treatment reversed such activation.

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