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.

Episodic ovarian inhibin secretion is not due to LH pulses in anoestrous ewes

1989 ◽  
Vol 123 (2) ◽  
pp. 173-179 ◽  
Author(s):  
B. K. Campbell ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Breeding Season ◽  
Plasma Levels ◽  
Single Injection ◽  
Venous Blood ◽  
Follicular Development ◽  
Blood Samples ◽  
A Site ◽  
Ovarian Inhibin ◽  
Secretion Rates

ABSTRACT In sheep, secretion of oestradiol by the ovary is stimulated by pulses of LH but the factors controlling ovarian inhibin secretion are not well understood. We have investigated the effect of a single injection of LH on the ovarian secretion of inhibin. Six anoestrous Finn–Merino ewes which had one ovary autotransplanted to a site in the neck had jugular and timed ovarian venous blood samples collected at 10-min intervals for a total of 5 h. The secretion rates of both inhibin (1–3 ng/min) and oestradiol (0·5–8 ng/min) were similar to those observed during the breeding season indicating significant follicular development in these animals. After injection of 2·5 μg NIH-LH-S25 intravenously the concentration of LH in plasma rose from a baseline of 1·8 ±0·1 (s.e.m.) μg/l to a peak of 3·9 ±0·3 μg/l (P<0·01). This LH pulse stimulated a corresponding increase (P<0·01) in oestradiol secretion from a basal level of 0·9±0·2 ng/min to a peak of 4·6±0·6 ng/min that occurred within 30 min of injection. Although inhibin secretion was episodic in nature, increases were not related to either exogenous or endogenous LH pulses. We conclude that, in contrast to oestradiol, the secretion of inhibin by the ovary is not controlled acutely by changes in plasma levels of LH during anoestrus. Journal of Endocrinology (1989) 123, 173–179

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.

scholarly journals Intrafollicular and Systemic Dopamine, Noradrenaline and Adrenaline Concentrations in Cycling Mares

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1896
Author(s):  
Katiuska Satué ◽  
Esterina Fazio ◽  
Maria Dolores Rubio ◽  
Cristina Cravana ◽  
Pietro Medica
Keyword(s):  
Breeding Season ◽  
Oocyte Maturation ◽  
Follicular Fluid ◽  
Meat Production ◽  
Hormone Concentration ◽  
Blood Samples ◽  
Clinically Normal ◽  
Follicle Diameter ◽  
Noradrenaline And Adrenaline

In some species, catecholamines in follicular fluid (FF) are related to local physiological events responsible for the regulation of ovarian functions and oocyte maturation. The aim of the present study was to determine and compare intrafollicular and systemic concentrations of dopamine (DA), noradrenaline (NA) and adrenaline (AD) in cycling mares. Sixty ovaries were collected during breeding season from 30 mares raised for slaughterhouse meat production, with clinically normal reproductive tracts, were evaluated. Blood samples were collected prior to slaughter. Follicles were classified into three categories in relation to size: small (20–30 mm; n = 20), medium (≥31–40 mm; n = 20) and large (≥41 mm; n = 20). Follicular fluid (FF) samples were extracted from each follicle. Intrafollicular DA, NA and AD concentrations were significantly higher than the systemic concentrations (p < 0.05). Intrafollicular DA concentrations were higher in medium than small and large follicles (p < 0.05). Intrafollicular NA concentrations were higher in small than medium and large follicles (p < 0.05). Intrafollicular AD concentrations were higher in large than small and medium follicles (p < 0.05). Follicle diameter was significantly and negatively correlated with NA and AD (p < 0.05). A significant correlation of the same hormone concentration in FF and in systemic fluid was observed (p < 0.05). In summary, the FF can serve as an intraovarian catecholamine-storing compartment, with the ability to release neurotransmitters in a regulated way. These results provide novel insights into the neuronal nature of the follicle, suggesting the involvement of catecholamines in normal ovarian functions in mares.

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.

scholarly journals Analysis of the variations of follicular fluid composition during follicular growth and maturation in the mare using proton nuclear magnetic resonance (1H NMR)

Reproduction ◽  
2002 ◽  
pp. 241-248 ◽  
Author(s):  
N Gerard ◽  
S Loiseau ◽  
G Duchamp ◽  
F Seguin
Keyword(s):  
Amino Acids ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Proton Nuclear Magnetic Resonance ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Follicular Maturation ◽  
H Nmr ◽  
Sugar Chains ◽  
Glucose Metabolites

Follicular development and ovulatory processes in mammals involve local biochemical changes as a result of substantial modifications in cellular metabolism, the most well known of which is steroid variation. In the present study, the intrafollicular variation of several other components was studied using proton nuclear magnetic resonance ((1)H NMR). This approach made it possible to demonstrate that the intrafollicular biochemical content changes during follicular growth and maturation. Follicular fluid was aspirated by ovarian puncture of the dominant follicle at various physiological stages of its development: early dominant, late dominant and preovulatory. Serum samples were collected during each puncture session. (1)H NMR was used to evaluate intrafollicular and circulating glycoconjugates (sugar chains and N-acetyl groups), lipoproteins (CH(3) and CH(2) groups), glucose metabolites (trimethylamines, acetate and lactate), amino acids (glutamine/glutamate and alanine), creatine/creatinine and polyamines. Follicular fluids were assayed by radioimmunoassay for oestradiol and progesterone contents. The intrafollicular contents of alanine and lipoproteins (CH(3) groups) decreased in the dominant follicle during growth, whereas concentrations of progesterone and oestradiol increased significantly. After injection of gonadotrophin to induce ovulation, follicular maturation was characterized by a decrease in glycoconjugates (sugar chains), trimethylamines and acetate, a decrease in oestradiol concentration, and a further increase in CH(3) groups of lipoproteins and progesterone. The results from the present study showed a clear correlation between the intrafollicular content of alanine and that of oestradiol. A correlation between progesterone and glycoconjugates (sugar chains) was also observed. Therefore, (1)H NMR was shown to be effective for studying specific changes in the biochemical composition of the follicular fluid that occur during follicular development. For the first time, the variation of several compounds (glycoconjugates, lipoproteins, glucose metabolites, amino acids and polyamines) in relation to growth and maturation was demonstrated. Some of these changes could be of crucial importance for follicular maturation and ovulation as well as for oocyte maturation and further fertilization.

scholarly journals Follicular growth patterns in repeat breeder cows

2012 ◽  
Vol 48 (No. 1 - 2) ◽  
pp. 1-8
Author(s):  
Pérez CC ◽  
I. Rodríguez ◽  
F. Espańa ◽  
J. Dorado ◽  
M. Hidalgo ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Follicular Development ◽  
Growth Patterns ◽  
Follicular Growth ◽  
Development Patterns ◽  
Follicular Waves ◽  
Repeat Breeder

The aim of this study was to examine follicular development patterns in eighteen repeat breeder cows through natural oestrus cycles. Ovarian ultrasonographic examinations over 32 days after artificial insemination revealed that two follicular waves were the predominant patterns in animals with this syndrome (72.2%). Cycles with one or four waves rarely appeared. The ovulatory follicular diameter (day 0) was larger (P &lt; 0.01) in cycles with a small number of waves; no differences were detected between ovulatory and anovulatory dominant follicles. Progesterone plasmatic concentrations were determined by RIA and differences were not significant when cycles with two or three waves were compared. The number of follicular waves was higher (2 or 3 waves) with longer interovulatory intervals (22.3 &plusmn; 1.89 vs 23.0 &plusmn; 2.0; n.s.) and older cows (7.0 &plusmn; 2.64 vs. 4.38 &plusmn; 1.66 years; P &lt; 0.05). Mean ovulatory follicular diameter was 1.78 &plusmn; 0.36 cm. It can be concluded that cows with the RBC syndrome more frequently present two follicular waves, corresponding to longer cycles. &nbsp;

Magnetic resonance image attributes of the bovine ovarian follicle antrum during development and regression

Reproduction ◽  
2000 ◽  
pp. 311-323 ◽  
Author(s):  
JL Hilton ◽  
GE Sarty ◽  
GP Adams ◽  
RA Pierson
Keyword(s):  
Magnetic Resonance ◽  
Relaxation Rate ◽  
Follicular Fluid ◽  
Magnetic Resonance Image ◽  
Follicular Development ◽  
Physiological Status ◽  
Proton Density ◽  
Dominant Follicle ◽  
Rate Heterogeneity ◽  
Pixel Value

The magnetic resonance images and maps of bovine ovaries acquired at defined phases of follicular development and regression were studied to determine whether magnetic resonance image attributes of the follicular antrum reflect the physiological status of dominant and subordinate ovarian follicles. Ovariectomies were performed at day 3 of wave one, day 6 of wave one, day 1 of wave two and at >/= day 17 after ovulation. The timings of ovariectomies were selected to acquire growing, early static, late static and regressing follicles of the first wave and preovulatory follicles of the ovulatory wave. Pre-selection and subordinate follicles were also available for analysis. Serum samples were taken on the day of ovariectomy and follicular fluid samples were taken after imaging. Numerical pixel value and pixel heterogeneity in a spot representing approximately 95% of the follicular antrum were quantified in T(1)- and T(2)-weighted images. T(1) and T(2) relaxation rates (T(1) and T(2)), proton density, apparent diffusion coefficients and their heterogeneities were determined from the computed magnetic resonance maps. The antra of early atretic dominant follicles showed higher T(2)-weighted mean pixel value (P < 0.008) and heterogeneity (P < 0. 01) and lower T(2) heterogeneity (P < 0.008) than growing follicles. Subordinate follicles in the presence of a preovulatory dominant follicle had higher T(1), T(1) heterogeneity, proton density, proton density heterogeneity, and lower mean pixel value in T(1)-weighted images than subordinate follicles of the anovulatory wave (P < 0.04). T(1) relaxation rate heterogeneity and proton density heterogeneity were positively correlated with follicular fluid oestradiol concentration (r = 0.4 and 0.3; P < 0.04). T(2) relaxation rate heterogeneity was positively correlated with follicular fluid progesterone concentration (r = 0.4; P < 0.008). Quantitative differences in magnetic resonance image attributes of the antrum observed among phases of follicular development and regression coincided with changes in the ability of the dominant follicle to produce steroid hormones and ovulate, and thus were indicative of physiological status and follicular health.

The effect of acute immuno-neutralisation of inhibin in ewes during the early luteal phase of the oestrous cycle on ovarian hormone secretion and follicular development

1995 ◽  
Vol 145 (3) ◽  
pp. 479-490 ◽  
Author(s):  
B K Campbell ◽  
B M Gordon ◽  
C G Tsonis ◽  
R J Scaramuzzi
Keyword(s):  
Luteal Phase ◽  
Follicular Development ◽  
Experimental Period ◽  
Ovarian Follicles ◽  
Passive Immunisation ◽  
Follicle Development ◽  
Ovarian Steroid ◽  
Blood Samples ◽  
Steroid Secretion ◽  
Antibody Titres

Abstract Ewes with ovarian autotransplants received either inhibin antiserum (10 ml i.v. raised in sheep against recombinant 32 kDa human inhibin; n=6) or sheep serum (10 ml i.v.; n=5) on day 3 of the luteal phase with additional daily injections (1 ml i.v.) from 48 h after the initial bolus until day 13. Jugular and ovarian venous blood samples were taken 4-hourly over days 2–13 of the luteal phase. Blood samples were also taken at more frequent intervals (every 10–15 min for 2–3 h) to examine pulsatile secretory responses from the ovary to endogenous and gonadotrophin-releasing hormone-induced (150 ng i.m.) LH pulses on days 4, 6, 8, 10 and 12 of the luteal phase. Plasma FSH levels, ovarian steroid secretion and ovarian follicular development were measured. The ovarian follicle population was estimated daily by real time ultrasound scanning. Immunisation against inhibin resulted in a 3- to 4-fold increase (P<0·001) in plasma FSH levels within 8 h with levels remaining elevated over controls for 6–7 days. Within 24 h of immunisation there was an increase in the number of small ovarian follicles (P<0·05) and by 3 days after treatment immunised ewes had 4–6 large ovarian follicles/ewe with this increase in the total number of large follicles being maintained for the rest of the experimental period (P<0·05). Mean ovarian oestradiol secretion during intensive bleeds was not different from controls 24 h after immunisation, but by 3 days after immunisation it was elevated 4- to 5-fold (P<0·001) over controls with this increase being maintained throughout the experiment. Similar responses to immunisation against inhibin in androstenedione secretion were observed although mean androstenedione secretion was not elevated until 7 days after treatment. In vitro antibody titres in immunised ewes remained elevated but declined steadily (P<0·001) over the experimental period. We conclude that the initial stimulation of follicle development and ovarian steroid secretion following passive immunisation against inhibin can be attributed to increased blood FSH. However, the fact that with time FSH declined but increased follicle development was sustained, despite maintenance of high circulating antibody titres, suggests that on a longer term basis inhibin immunisation may stimulate ovarian function by interfering with the modulation of follicle development by inhibin at an ovarian level. Journal of Endocrinology (1995) 145, 479–490

scholarly journals Comparison of PUFA Profiles in the Blood and in Follicular Fluid and its Association with Follicular Dynamics after PGF2α Induced Luteolysis in Dairy Cows

2016 ◽  
Vol 39 (2) ◽  
pp. 175-183
Author(s):  
Branko Atanasov ◽  
Miel Hostens ◽  
Zehra Hajrulai-Musliu ◽  
Risto Uzunov ◽  
Nikola Adamov ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fatty Acid ◽  
Dairy Cows ◽  
Negative Correlation ◽  
Follicular Fluid ◽  
Follicular Growth ◽  
Alpha Linolenic Acid ◽  
Daily Growth ◽  
Strong Negative Correlation ◽  
Follicular Dynamics

AbstractThe objectives of the present study were to examine the fatty acid (FA) profiles in serum and in the follicular fluid (FF) and the association between polyunsaturated fatty acid level (PUFA) and follicular growth dynamics following induced luteolysis in dairy cows. A total of 29 dairy cows (CL>25mm, follicle≈15mm) at d0 (start of the experiment) were submitted to ultrasound guided transvaginal follicular aspiration for FF collection from the largest follicle and were injected with 500 μg of cloprostenol. The cows were subdivided into Group A1 (n=11) and Group A2 (n=8) resuming follicular growth either from a secondary follicle less than or larger than 8.5mm, respectively, present at the moment of aspiration and Group A0 (n=10) not resuming follicular growth. Follicular development was monitored daily by ultrasonography until the next dominant follicle reached ≈15mm and was subsequently punctured in Group A1 and A2 (d1). Serum and FF samples for FA determination were taken at d0 from all cows and at d1 in Group A1 and A2. No differences were observed between the FA profile in serum nor in FF between sampling days. Regarding the PUFA levels, the serum linoleic acid (C18:2n6) levels at d0 and d1 were significantly higher than in FF, while alpha linolenic acid (C18:3n3) was lower in the serum than in FF, both at d0 and d1. At d0, a tendency for negative correlation between serum and the FF C18:2n6 with subsequent daily follicular growth rate was observed, while, at d1 there was a strong negative correlation between the serum C18:2n6 and daily growth rate (r=−0.71; p=0.0006). The present study revealed similarities of the FA profiles in the serum and in the FF and association between serum and FF PUFA content with the follicular dynamics after induced luteolysis.

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