Ovulation Of Dominant Follicle Research Articles

Follicular development in long-term anoestrous suckler beef cows fed two levels of energy postpartum

Follicular growth patterns were monitored daily by ultrasonography, from calving until completion of the first ovarian cycle postpartum in beef cows fed either a low (L; n = 11) or high (H; n = 12) energy diet. Mean cow body condition score at calving was 2.1 (range 1.75–2.25). The mean (± standard error of the mean) number of days postpartum to detection of the first follicle wave was 10.4±0.9 and 9.6±0.9 days for the L and H groups respectively ( P>0.10). L diet cows tended to have more ( P=0.09) medium-dominant follicle waves before first ovulation than H diet cows. Because the first two follicle waves postpartum consisted of the medium follicles, this resulted in a slightly longer ( P>0.10) interval to detection of the first dominant follicle wave in the L cows than in the H cows. The total number of follicle waves before first ovulation was 10.6±1.2 anand 6.8±1.2 ( P<0.05) for L and H cows, respectively. The growth rate, maximum diameter, persistence and regression rate of anovulatory dominant or medium-dominant follicles were not affected by level of diet ( P>0.10) but did change ( P<0.05) as wave number postpartum increased. Peripheral concentrations of oestrogen were low and were not related to follicular growth during the non-ovulatory period. The oestrogen concentrations were significantly higher immediately before first and second ovulations, and paralleled the growth of the first and second ovulatory follicles. The mean interval from calving to first ovulation was longer ( P<0.05) for the L cows (95 ± 12 days) than for H (70 ± 12 days) cows. All of the cows on the L diet (11/11) had a short cycle following first ovulation while 8/12 of the H cows had a short cycle, 3/12 had a normal cycle and 1/12 had a long cycle after first ovulation. In summary, beef suckler cows with a prolonged postpartum interval to first ovulation have an early resumption of the development of dominant follicles whose growth characteristics are largely unaffected by plane of nutrition; these dominant follicles undergo recurrent development and atresia. In conclusion, the problem of prolonged postpartum anoestrus in beef cows is due to failure of ovulation of dominant follicles rather than a lack of development of dominant follicles.

Selection, dominance and atresia of follicles during the oestrous cycle of heifers.

This study examined the correlation between measurement of follicle growth by ultrasound, and measurement of intrafollicular ratios of oestradiol and progesterone concentrations and the serum concentrations of FSH during selection, dominance and atresia or ovulation of dominant follicles in heifers. Heifers were ovariectomized on days 0 (before LH surge), 1 (after LH surge, preovulation), 1 (postovulation), 3, 6 and 12 of the oestrous cycle. Blood samples were collected at 4-6 h intervals. After ovariectomy all follicles > or = 5 mm were measured and follicular fluid was aspirated. Follicles were classified by size according to ultrasound (F1, largest; F2, second largest; F3, all remaining follicles > or = 5 mm) and by the ratio of oestradiol:progesterone concentrations. During the follicular phase, a single dominant oestrogen-active follicle increased in diameter while serum concentrations of LH increased and FSH decreased (P < 0.05). On day 1 (after LH surge, preovulation), serum LH and FSH decreased to pre-surge concentrations (P < 0.0001), while follicle size and intrafollicular progesterone concentration increased and oestradiol concentration decreased (P < 0.05). A dominant nonovulatory follicle, classified as oestrogen-active on days 1, 3 and 6 and oestrogen-inactive on day 12, increased in size from day 1 to day 7 and lost dominance during days 10-12, coincident with the growth of multiple oestrogen-active follicles. The serum FSH concentration increased transiently (P < 0.05) before each new wave of dominant follicular growth. The overall correlation of ultrasound measurements of follicle diameter with measures of follicle size after ovariectomy was high.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of atresia or of luteinization without rupture of the dominant ovarian follicle in rhesus monkeys treated with estradiol-17β on day 8 of the menstrual cycle.

Previous results have established that 17β-estradiol (E2) administered in capsules for 24 h on Day 6 of the menstrual cycle results in atresia of the dominant follicle (DF). The present experiment was designed to determine if atresia could be induced similarly as late as Day 8, when the DF is presumably larger, to facilitate biochemical analyses. On the morning of Day 8, laparoscopy was used to confirm the presence of the DF, and 4, 6, or 8 Silastic capsules containing E2 were placed s.c. for 12 or 24 h. Treatment with E2 for 12 h resulted in atresia of the dominant follicle: 2/4,4/5, and 2/5 with 4, 6, and 8 capsules, respectively. Increases in luteinizing hormone (LH) usually occurred following removal of E2 after 12 h; similar increases resulted previously from treatment on Day 6, and are interpreted as the result of removal of E2-induced negative feedback rather than an effect of positive feedback. In contrast to the efficacy of treatment for 12 h, treatment with E2 for 24 h resulted in a lower incidence of atresia (2/5,1/6, and 1/4 with 4, 6, and 8 capsules), and premature LH surges were seen during treatment in almost all animals, especially with 6 or 8 capsules, initiating luteinization of the DF without ovulation. Regarding intrafollicular changes, E2 treatment resulted in a 10-fold reduction in follicular fluid concentrations of estrogen, while progesterone (P) levels were augmented; the output of P by granulosa cells in culture was also enhanced by E2 treatment. We conclude that the DF in monkeys remains susceptible to the atretogenic effects of E2 as late as Day 8 of the cycle, but the amount of follicular material recoverable is not increased with the later treatment. Furthermore, the similarity between the luteinized unruptured follicles induced in this study and those occurring spontaneously in women suggests that this model may be valuable in elucidating the factors involved in this source of infertility in women. © 1994 Wiley-Liss, Inc.

Pattern of follicular growth and resumption of ovarian activity in post-partum beef suckler cows

The ovaries of 18 post-partum beef suckler cows were examined daily, using ultrasound, from Day 5 post partum until a normal oestrous cycle was completed. Periods of growth and regression of medium-sized (5-9 mm) follicles were identified before one medium follicle became dominant (single large follicle greater than or equal to 10 mm). The mean (+/- s.e.m.) number of days from parturition to detection of the first post-partum dominant follicle was 10.2 +/- 0.5. The first post-partum dominant follicle ovulated in 2/18 (11%) cows. The interval from calving to first ovulation (mean +/- s.e.m. = 35.9 +/- 3.3 days) was characterized by the growth and regression of a variable number (mean = 3.2 +/- 0.2; range 1-6) of dominant follicles. The maximum diameter of the dominant follicle increased as the cows approached first ovulation (P less than 0.05). Behavioural oestrus was not detected in 16/18 (89%) cows at first ovulation. Following first ovulation, the length of the subsequent cycle was short (mean = 9.7 +/- 0.5 days; range 8-15 days) in 14/18 (78%) cows and was characterized by the development and ovulation of a single dominant follicle. During oestrous cycles of normal length (mean = 20.6 +/- 0.5 days; range 18-23 days) one (N = 2), two (N = 7) or three (N = 8) dominant follicles were identified. The growth rate, maximum diameter or persistence of non-ovulatory dominant follicles before first ovulation or during oestrous cycles were not different (P greater than 0.05). These data show that, in beef suckler cows, follicular development and formation of a dominant follicle occur early after parturition and the incidence of ovulation of the first dominant follicle is low. The number of dominant follicles that develop before first ovulation is variable; first ovulation is rarely associated with oestrus and short cycles are common after first ovulation. It is concluded that prolonged anoestrus in post-partum beef suckler cows is due to lack of ovulation of a dominant follicle rather than delayed development of dominant follicles.

Direct effect of estradiol-17β on progesterone accumulation by ovarian granulosa cells from rhesus monkeys.

We have previously demonstrated that estradiol-17β (E2) administered in vivo induces atresia of the dominant ovarian follicle (DF). Whether this effect is exerted directly at the ovarian level or by central mediation has not been confirmed. The present study was designed to assess whether E2 in amounts similar to those found in monkey follicular fluid (FF) directly alters in vitro progesterone (P) accumulation by granulosa cells (GC) aspirated from follicles in cycling rhesus monkeys. Follicular contents were aspirated from three to five animals on each of days 8-13 of the cycle. GC were plated at a density of 50,000 viable GC/0.5 ml medium; GC were incubated with 0 or 2-2,000 ng/ml E2, and cultures were maintained for 72 h. P accumulation by GC collected on day 8 and treated with 2 ng/ml E2 was augmented 37.5 ± 5.5% (X ± S. E. M.; P<.05) over controls but was diminished significantly at 20 ng/ml ( -55 ± 18% with respect to controls), 200 ng/ml ( -73.7 ± 13.2%), and 2,000 ng/ml ( -77.3 ± 18.4%). A similar dose-response relationship was noted on other cycle days. At a concentration of 2,000 ng/ml, E2 significantly reduced P 91.5 ± 8.5% (day 10), 81.5 ± 18.5% (day 11), 84.3 ± 4.7% (day 12), and 53.7 ± 15.8% (day 13). We conclude that E2 at concentrations found in FF can inhibit P output by monkey GC through a direct action.

Atresia of the dominant ovarian follicle in rhesus monkeys is detected within 24 hours of estradiol treatment.

Following treatment with estradiol-17β (E2) on day 6 of the menstrual cycle, degenerative alterations in the microenvironment of the dominant follicle (DF) (follicular fluid [FF], granulosa cells [GC], and oocyte) are readily apparent on day 10, or 96 h after E2 administration. The present study was designed to determine how early such changes could be detected and which indices of atresia were observed first. The DF was identified during laparoscopy on day 5 or 6 of the cycle, and four capsules containing crystalline E2 were inserted s.c. for 24 h. Contents of the DF were aspirated at 24, 48, and 72 h following initiation of E2 treatment. General size and appearance of the DF did not change distinctly with E2 treatment; however, by 48 h FF viscosity was increased markedly. GC viability was not altered with treatment. FF concentrations of estrogen (E) were dramatically reduced at 24 h. These differences were maintained at 48 h and at 72 h. E accumulation by cultured GC was significantly reduced by > eightfold. There appeared a similar trend for reduced progesterone (P) in FF and decreased P production by GC in vitro. These results demonstrate that degenerative alterations in the DF indicative of atresia can be detected as early as 24 h after initiation of E2 treatment; the index of atresia appearing earliest is a reduction in FF concentrations of E, and the first morphological changes in the DF can be observed 24 h later. This study indicates that biochemical alterations precede morphologic changes with E2-induced atresia, and should allow us to begin to determine the earliest events and putative initiation sites of atresia.

Ovarian hyperstimulation syndrome: prediction by number and size of preovulatory ovarian follicles

Monitoring of human menopausal gonadotropin (hMG) treatment for induction of ovulation according to either preovulatory estrogen levels or the presence of a dominant ovarian follicle was found insufficient to prevent ovarian hyperstimulation syndrome (OHS). In 65 infertile patients treated with hMG and human chorionic gonadotropin (hCG), a possible correlation between the number and size of all ovarian follicles on the day of assumed ovulation and the occurrence of OHS was evaluated in order to assess the value of ultrasonography in predicting OHS. It was found that patients with OHS had significantly more follicles at the time of hCG than patients without OHS. Mild OHS was characterized by the presence of eight to nine follicles, 68.7% of which were of intermediate size (9 to 15 mm). In moderate to severe OHS 95% of the preovulatory follicles were less than 16 mm, most of them (54.7%) less than 9 mm in diameter. It can be concluded that a specific preovulatory follicular configuration characterizes mild and severe hyperstimulation. This is important information before hCG administration and emphasizes the value of ovarian ultrasonography in predicting OHS.

Selection of the dominant ovarian follicle and hormonal enhancement of the natural cycle.

Annals of the New York Academy of SciencesVolume 442, Issue 1 p. 23-37 Selection of the Dominant Ovarian Follicle and Hormonal Enhancement of the Natural Cycle GARY D. HODGEN, GARY D. HODGEN Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this authorDANIEL KENIGSBURG, DANIEL KENIGSBURG Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this authorROBERT L. COLLINS, ROBERT L. COLLINS Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this authorROBERT S. SCHENKEN, ROBERT S. SCHENKEN Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this author GARY D. HODGEN, GARY D. HODGEN Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this authorDANIEL KENIGSBURG, DANIEL KENIGSBURG Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this authorROBERT L. COLLINS, ROBERT L. COLLINS Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this authorROBERT S. SCHENKEN, ROBERT S. SCHENKEN Pregnancy Research Branch National Institute of Child Health and Human Development National Institutes of Health Bethesda, Maryland 20205Search for more papers by this author First published: May 1985 https://doi.org/10.1111/j.1749-6632.1985.tb37502.xCitations: 17AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume442, Issue1In Vitro Fertilisation and Embryo TransferMay 1985Pages 23-37 RelatedInformation

Arrest of folliculogenesis and inhibition of ovulation in the monkey following weekly administration of progestins

Studies were undertaken in the rhesus monkey to determine whether development of a dominant ovarian follicle could be repeatedly arrested by the administration of a progestin on day 7 of the menstrual cycle, and then every 7 days thereafter regardless of menstrual bleeding history. Progesterone (7.5 mg), norethisterone (1.5 mg), and 17 alpha-ethinyl-17 beta-methoxy-7 alpha-methyl-4-estren-3-one (1.0 or 1.5 mg) effectively inhibited ovulation when injected intramuscularly once a week for 8 weeks. Orally administered STS 557 (17 alpha-cyanomethyl-17 beta-hydroxy-4,9-estradien-3-one, 1.0 mg) also inhibited ovulation. Two structurally related steroids (17 beta-methoxy-4-estren-3-one, 1.0 mg; and 17 beta-methoxy-7 alpha-methyl-4-estren-3-one, 1.5 mg) did not inhibit ovulation when given intramuscularly at the indicated doses. Although weekly administration of certain progestins effectively arrested follicular development and inhibited ovulation in the primate, the treatment was accompanied by disturbances in menstrual bleeding patterns.

Distinguishing the steroidogenic roles of granulosa and theca cells of the dominant ovarian follicle and corpus luteum.

In order to determine the relative contribution of granulosa cells and follicular fluid of the preovulatory follicle to ovarian and peripheral vein levels of principal steroids in the late follicular phase, as well as the importance of granulosa cells and theca cells in subsequent corpus luteum function, 32 rhesus and cynomolgus monkeys were studied. In group one (n = 10), they were bled from the femoral vein daily throughout the cycle and sera assayed for FSH, LH, estradiol, and progesterone. In addition, they were laparotomized in the late follicular phase when serum estradiol (by rapid assay) had exceeded 150 pg/ml for about 24 h. Ovarian vein blood was taken ipsilateral to the dominant follicle, followed by aspiration of follicular contents and rinsing of the antrum to remove as many granulosa cells as possible without disturbing the thecal layers. Also, blood from the contralateral ovarian vein was obtained, as well as a second collection from the ipsilateral ovarian vein 15 min after follicular aspiration; a second peripheral sample was obtained immediately thereafter. Ovarian vein asymmetry of estradiol, progesterone, and androstenedione, but not 17-OH progesterone, was noted in every case (i.e. higher steroid levels were associated with the putative dominant follicle). After follicular aspiration, high concentrations of estradiol, progesterone, and androstenedione in ovarian venous effluent fell (P less than 0.001) by nearly 70% from preaspiration levels; concurrently, peripheral levels of estradiol and progesterone were reduced by about 40%. Conversely, 17-OH progesterone was unaffected. Integrated progesterone levels throughout the subsequent luteal phase, but not serum estradiol, were significantly (P less than 0.001) less in the experimental monkeys (after aspirating/rinsing) compared to controls, although luteal phase length was unchanged (14.33 vs. 14.83 days). Groups two (n = 7) and three (n = 15) were employed to assess the influence of vascular trauma caused by either continuous cannulation or serial (up to six insults) venipuncture, on the concentrations of the principal ovarian steroids in ovarian vein blood.(ABSTRACT TRUNCATED AT 400 WORDS)

The dominant ovarian follicle

The dominant ovarian follicle

Developing morphological asymmetry of ovarian follicular maturation in monkeys.

In order to study recruitment and selection of the dominant ovarian follicle in the menstrual cycle, we used luteectomy to synchronize the onset of new follicle growth. Previous experiments showed that the next ovulation after surgical removal of the corpus luteum usually occurs within approximately 14 days and is most often on the contralateral ovary. Twenty regularly cycling rhesus monkeys were luteectomized in midluteal phase and assigned to one of four groups. Ten of these monkeys were unilaterally ovariectomized 4 days after luteectomy; 5 underwent removal of the ipsilateral ovary (Day 4-I) and in 5 the contralateral ovary (Day 4-C) was excised. The remaining 10 were hemiovariectomized 8 days after luteectomy; again, 5 were hemiovariectomized on the same side as luteectomy (Day 8-I) and 5 on the contralateral aide (Day 8-C). Ovaries were serially sectioned; all antral follicles were classified and measured. Results indicate a significant increase (P<0.05) in medium size (0.5-1.0 mm) developing follicles in the Day 4-C versus the Day 4-I ovaries, even though an overt dominant follicle was not identified in either group. The next preovulatory luteinizing hormone (LH) surge occurred about 13 days after hemiovariectomy for both groups. In ovaries of the Day 8C group, there was a significant decrease (P<0.05) in medium size developing antral follicles and a significant increase in medium size early atretic follicles. Following contralateral hemiovariectomy on Day 8, the next LH surge was deferred until 18 days after luteectomy, suggesting that the new dominant follicle was removed along with the excised ovary. This is in contrast to the Day 8-I group, in which the distribution of follicles resembled that in the Day 4-I ovaries; the next LH surge was not delayed, occurring approximately 5 days after hemiovariectomy. These findings demonstrate: 1) that morphological asymmetry of certain sized developing antral follicles was detectable as early as Day 4 after luteectomy; 2) that follicle growth within the ipsilateral ovary was retarded even 8 days after luteectomy; and 3) that selection of the dominant follicle was not completed within 4 days in this experimental model, but was absolute by 8 days after luteectomy.

The dominant ovarian follicle

The dominant ovarian follicle

Studies in Bovine Malignant Catarrh: VI. Adaptation to Rabbits

There is a variable anoestrous period following parturition in the cow. Follicular growth generally resumes within 7 to 10 days in the majority of cows associated with a transient FSH rise that occurs within 3 to 5 days of parturition. Dairy cows that are not nutritionally stressed generally ovulate their first postpartum dominant follicle (~15 days), whereas beef suckler cows in good body condition normally have a mean of 3.2±0.2 dominant follicles (~30 days) to first ovulation; moreover, beef cows in poor body condition have a mean of 10.6±1.2 dominant follicles (~70 to 100 days) to first ovulation. The lack of ovulation of dominant follicles during the postpartum period is associated with infrequent LH pulses, with both maternal–offspring bonding and low body condition score (BCS) at calving being implicated as the predominant causes of delayed resumption of cyclicity in nursed beef cows. In dairy cows, the normal pattern of early resumption of ovulation may be delayed in high-yielding Holstein type cows generally owing to the effects of severe negative energy balance, dystocia, retained placental membranes and uterine infections. First ovulation, in both dairy and beef cows, is generally silent (i.e., no behavioural oestrus) and followed by a short inter-ovulatory interval (>70%). The key to optimizing the resumption of ovulation in both beef and dairy cows is appropriate pre-calving nutrition and management so that cows calve down in optimal body condition (BCS; 2.75 to 3.0) with postpartum body condition loss restricted to <0.5 BCS units.