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

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

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

Selection of fewer dominant follicles in Trio carriers given GnRH antagonist and luteinizing hormone action replaced by nonpulsatile human chorionic gonadotropin†

2020 ◽  
Vol 103 (6) ◽  
pp. 1217-1228
Author(s):  
Victor E Gomez-León ◽  
João Paulo Andrade ◽  
Brian W Kirkpatrick ◽  
Sadrollah Molaei Moghbeli ◽  
Alvaro García-Guerra ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Gnrh Antagonist ◽  
Maximum Diameter ◽  
High Fecundity ◽  
Follicle Diameter ◽  
Follicle Selection ◽  
Selection Of

Abstract Studying selection of multiple dominant follicles (DFs) in monovulatory species can advance our understanding of mechanisms regulating selection of single or multiple DFs. Carriers of the bovine high fecundity Trio allele select multiple DFs, whereas half-sib noncarriers select a single DF. This study compared follicle selection during endogenous gonadotropin pulses versus during ablation of pulses with Acyline (GnRH antagonist) and luteinizing hormone (LH) action replaced with nonpulsatile human chorionic gonadotropin (hCG) treatment in Trio carriers (n = 28) versus noncarriers (n = 32). On Day 1.5 (Day 0 = ovulation), heifers were randomized: (1) Control, untreated; (2) Acyline, two i.m. doses (Days 1.5 and D3) of 3 μg/kg; (3) hCG, single i.m. dose of 50 IU hCG on Day 1.5 followed by daily doses of 100 IU; and (4) Acyline + hCG. Treatments with nonpulsatile hCG were designed to replace LH action in heifers treated with Acyline. Acyline treatment resulted in cessation of follicle growth on Day 3 with smaller (P < 0.0001) maximum follicle diameter in Trio carriers (6.6 ± 0.2 mm) than noncarriers (8.7 ± 0.4 mm). Replacement of LH action (hCG) reestablished follicle diameter deviation and maximum diameter of DFs in both genotypes (8.9 ± 0.3 mm and 13.1 ± 0.5 mm; P < 0.0001). Circulating follicle stimulating hormone (FSH) was greater in Acyline-treated than in controls. Finally, Acyline + hCG decreased (P < 0.0001) the number of DFs from 2.7 ± 0.2 to 1.3 ± 0.2 in Trio carriers, with most heifers having only one DF. This demonstrates the necessity for LH in acquisition of dominance in Trio carriers (~6.5 mm) and noncarriers (~8.5 mm) and provides evidence for a role of GnRH-induced FSH/LH pulses in selection of multiple DFs in Trio carriers and possibly other physiologic situations with increased ovulation rate.

scholarly journals Ovarian Follicular Dynamics during the Estrous Cycle in Jennies in Upper Egypt

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
R. I. Derar ◽  
H. A. Hussein
Keyword(s):  
Growth Rate ◽  
Estrous Cycle ◽  
Slow Rate ◽  
Ovarian Follicles ◽  
Maximum Diameter ◽  
Dominant Follicle ◽  
Upper Egypt ◽  
Follicular Wave ◽  
Preovulatory Follicles ◽  
Follicular Dynamics

The objective of the current study was to describe follicular dynamics in Egyptian Jennies throughout the estrous cycle. In this experiment, 8 estrus cycles in 8 cyclic Jennies were studied from February to June using ultrasonography. The result revealed that one follicular wave per cycle was recorded throughout the studied period. Dominant follicle (DF) was firstly detected at day in Jennies. The growth rate of DF was  mm/day. Left ovulations were nonsignificantly () more than right ovulations (55.6% versus 44.6%). The CL was firstly detected at D , developed in a rate of  mm/day, reached a maximum diameter of  mm at D , and started to regress on D with a mean regression rate of  mm d-1. Results of the present study indicated that Jennies had one follicular wave per cycle. The Day of the cycle has a significant effect on the number of different classes of the ovarian follicles, but not large ones. Ultrasonographic characteristics of the preovulatory follicles could be useful to predict ovulation. CL developed and regressed in a slow rate.

Variation in rectal temperature of cattle in a tropical environment and its relation to growth rate

1984 ◽  
Vol 38 (3) ◽  
pp. 417-427 ◽  
Author(s):  
H. G. Turner
Keyword(s):  
Growth Rate ◽  
Genetic Correlation ◽  
Rectal Temperature ◽  
Bos Indicus ◽  
Heritability Estimate ◽  
Growth Period ◽  
The Other ◽  
Tropical Environment ◽  
The Mean ◽  
Selection Of

ABSTRACTRectal temperatures of cattle grazed near the tropic of Capricorn in central Queensland were studied. The cattle were of Bos indicus, B. taurus and crossbred lines, and were represented by over 200 growing heifers in each of 2 years and some supplementary groups.Rectal temperatures were loge normally distributed when they were expressed as deviations from a basal temperature of 38°C. They were significantly repeatable, but were more highly repeatable when herd mean temperature was above 39·5°C. The heritability estimate was 0·33 (P < 0·01).The mean phenotypic regression of growth rate on rectal temperature, within breed groups, was 0·04 (s.e. 0·006) kg/day per °C (r = 0·3, P < 0·01) over the entire growth period from birth to 18 months of age but greater during warmer seasons. The estimated genetic correlation was insignificant in one group of heifers but −0·86 (s.e. 0·17) in the other.The evidence of favourable and possible unfavourable responses to selection of cattle for low rectal temperature in warm environments is discussed.

Adrenal Incidentaloma and Subclinical Cushing’s Syndrome: A Longitudinal Follow-Up Study by Endoscopic Ultrasound

2015 ◽  
Vol 38 (04) ◽  
pp. 411-419 ◽  
Author(s):  
Maike Collienne ◽  
Nina Timmesfeld ◽  
Simona Bergmann ◽  
Joachim Goebel ◽  
Peter Kann
Keyword(s):  
Growth Rate ◽  
Cushing’S Syndrome ◽  
Endoscopic Ultrasound ◽  
Adrenal Incidentaloma ◽  
Cushing's Syndrome ◽  
Endocrine Function ◽  
Maximum Diameter ◽  
Subclinical Cushing’S Syndrome ◽  
The Mean

Abstract Purpose Adrenal incidentaloma (AI) and adrenal masses in cases of subclinical Cushing’s syndrome (SCS) initially require follow-up imaging. In this study we used endoscopic ultrasound (EUS) as a method for high-resolution imaging. The aim was to evaluate the growth rate of AI and SCS by EUS. Materials and Methods This retrospective analysis included 93 out of 229 patients with AI or SCS who were investigated longitudinally by EUS in our university hospital between 1997 and 2013. The longitudinal follow-up required at least two investigations by EUS and evaluation of endocrine function. Plasma renin, serum aldosterone, 24 h urinary catecholamines and 2 mg dexamethasone suppression test were performed. EUS was performed at baseline and during follow-up. Each time, the maximum diameter was measured. Three groups were defined: non-functioning adenomas (NFA), non-functioning nodular hyperplasias (NFH) and SCS. Results 86 patients had non-functioning masses [NFM] (59 NFA, 48 NFH) and 7 patients had SCS (10 masses). At baseline the mean diameter was 19.4 (± 9.3) mm (NFM) and 19.6 (± 9.2) mm (SCS). The mean follow-up period was 31.6 ± 28.7 months. The estimated mean growth rates per year were low: They were 0.35 mm/yr [NFA], 0.02 mm/yr [NFH] and 0.53 mm/yr [SCS]. Furthermore, there was no malignant progression of any mass. Conclusion The growth rate as determined by EUS was low for all tumor entities observed in this study. There was no difference in tumor growth between the groups.

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

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

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

86 Ultrasonographic evaluation of preovulatory follicle and endometrial echo texture for ovulation prediction in Marwari mares

2021 ◽  
Vol 33 (2) ◽  
pp. 151
Author(s):  
D. Yadav ◽  
D. Jhamb ◽  
S. S. Nirwan ◽  
M. Gaur
Keyword(s):  
Growth Rate ◽  
Correlation Coefficients ◽  
Uterine Horn ◽  
Oestrous Cycle ◽  
Preovulatory Follicle ◽  
Cross Sectional ◽  
Average Growth ◽  
Pixel Intensity ◽  
Follicle Diameter ◽  
The Mean

The objective of the present study was to evaluate the application of ultrasonographic changes in the preovulatory follicle and uterus for ovulation prediction in Marwari mares. Mares (n=20) were teased daily by a teaser pony and, from the day of first detected oestrus, the ovaries and uterus were examined by transrectal ultrasonography using Exago ECM ultrasound equipped with linear rectal probe (10MHz) until ovulation. Recorded data were analysed by one-way ANOVA and correlation coefficients. The duration of the oestrus period ranged from 5 to 7 days in all mares, with an average of 6.35±0.13 days, consistent with rectal findings. The last day of oestrus was marked by disappearance of the preovulatory follicle and presence of a corpus haemorrhagicum. The mean diameter of the follicles increased significantly (P&lt;0.01) from Day 1 to Day 7, and the diameter of follicles before ovulation was 44.88±0.46 mm; follicles changed from round to oval or irregular before ovulation. In 65% (13/20) of the mares, ovulation occurred on the left ovary. The daily mean growth rate of size of ovulating follicles from the first day of oestrus until ovulation was 3.51±0.42 mm/d. The mean average growth rate of follicles was significantly different (P ≤ 0.01) on different days of oestrus. The mean endometrial echo texture score was 1.30±0.10 on Day 1, 2.10±0.16 on Day 2, 3.20±0.15 on Day 3, and highest 3.85±0.08 on Day 4, declining thereafter to reach a score of 1.36±0.11 on Day 7 of the oestrous cycle. The mean slope values of pixel intensity for the granulosa and anechoic layers of the preovulatory follicles determined by Image-Pro software (Media Cybernetics) from Days −3 to −1 was 13.8±0.7 on Day −3, 15.7±0.9 on Day −2, and 20.1±1.3 on Day −1. None of the follicles ovulated before granulosa layer echogenicity reached a score of ≥2.5 and prominence of anechoic layer reached a score of ≥2. Significant positive correlations were found between the cross-sectional diameter of the uterine horn and estrual endometrial echotexture score (P&lt;0.01; r=0.95), estrual endometrial echo texture score and preovulatory follicle diameter (P&lt;0.01; r=0.25), and preovulatory follicle diameter and cross-sectional diameter of uterine horn (P&lt;0.01; r=0.36) during the oestrous cycle. We conclude that various ultrasonographic characteristics of preovulatory follicle and uterus can be used to predict ovulation in Marwari mares.

THE SOURCE OF OVARIAN OESTRADIOL AND ANDROSTENEDIONE IN THE SHEEP DURING THE LUTEAL PHASE

1976 ◽  
Vol 83 (2) ◽  
pp. 402-409 ◽  
Author(s):  
D. T. Baird ◽  
R. J. Scaramuzzi
Keyword(s):  
Blood Flow ◽  
Corpus Luteum ◽  
Luteal Phase ◽  
Contralateral Side ◽  
Large Follicle ◽  
Graafian Follicle ◽  
Follicle Diameter ◽  
The Mean ◽  
Low Levels

ABSTRACT The secretion of oestradiol and androstenedione was investigated in sheep by cannulating both ovarian veins in situ. The mean ovarian blood flow (ml/min ± se) was significantly higher on the side containing the corpus luteum (7.67 ± 1.36) than on the contralateral side (4.93 ± 0.85). The mean secretion (ng/min ± se) of oestradiol (1.09 ± 0.36) and androstenedione (1.52 ± 0.16) was higher on the side containing at least one large follicle (diameter > 4 mm) than on the contralateral side (0.19 ± 0.05 and 0.62 ± 0.21, respectively). The secretion of oestradiol was unchanged following enucleation of the corpus luteum but fell to very low levels (0.062 ± 0.022 ng/min) after enucleation of follicles diameter > 4 mm. The secretion of androstenedione fell significantly after enucleation of both corpus luteum and large follicles. These results suggest that during the luteal phase in the sheep oestradiol is secreted virtually exclusively by the largest non-atretic Graafian follicle. Androstenedione in contrast arises from both follicle, corpus luteum and possibly stroma.

scholarly journals Ovarian follicular dynamics in buffaloes during different estrus synchronization protocols

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Wael M.B. Noseir ◽  
Iman E. El-Bawab ◽  
Walid R. Hassan ◽  
Mostafa S. Fadel
Keyword(s):  
Hormonal Treatment ◽  
Progesterone Level ◽  
Dominant Follicle ◽  
Group 4 ◽  
Follicle Diameter ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Mean Concentration ◽  
Estradiol Levels

The current study was carried out on 26 normal cycling buffaloes. Animals were divided into 4 groups according to the hormonal treatment regime. Group 1 included 11 buffaloes without hormonal treatment. Group 2: five buffaloes injected with one dose of 25 mg prostaglandin F2alpha (PGF2α) after ultrasound diagnosis of a mature corpus luteaum in one ovary. Group 3: five buffaloes injected blindly with two doses of 25 mg PGF2α 11-days interval. Group 4: five buffaloes treated with ovsynch protocol. The pattern of follicular growth (FG) and the corpus luteum (CL) regression were monitored by transrectal ultrasound scanning. Estradiol 17β and progesterone profiles were estimated by radioimmunoassay for all groups. Buffaloes in Group 1 showed two (72.7%) or three (27.3%) waves-like patterns of follicular development. The average length of the estrous cycle was 21.75±0.53 and 27.0±0.58 days in 2- and 3- wave cycle respectively. The duration of the CL was 16.63±0.53 and 22.3±0.88 days in 2- and 3- wave cycles. One buffalo in Group 2 did not respond to injection of a single dose of PGF2α, while the other 4 responded. On the day of injection the diameter of the CL was 1.90±0.11 cm and that of dominant follicle was 0.97±0.07 cm. On day 2 after injection the follicle diameter was 1.4±0.09 cm and the preovulatory follicle on days 3-4 was 1.5±0.03 cm. The regressing CL diameter was 1.3±0.07 cm and progesterone level decreased from 6.27±0.82 ng/mL on day 0, to 0.13±0.06 ng/mL on days 3-4 post injection. Estradiol levels were increased from 5.40±1.2 pg/mL on day 0, to 15.09±1.97 pg/mL on day 3-4 post injection. After injection of the first dose of PGF2α, in group 3 the maximum follicle diameter was 1.10±0.04 cm on day 6, then started to regress (0.60±0.04 cm) on days 13-17 after injection. In the 2nd wave, the ovulatory follicle showed marked increase from day 2 (0.34±0.01 cm) till days 13-17 (1.33±0.08 cm). The diameter of CL increased from 1.53±0.03 cm on day 0 of treatment to 1.71±0.04 cm on day 7 of treatment. The second dose of PGF2α resulted in rapid decrease in the diameter of dominant follicle of the first wave from 0.88±0.05 cm on day 11 of treatment to 0.60±0.04 cm on days 13-17 (day of estrus) and rapid increase in the diameter of dominant follicle of the second wave from 0.89±0.08 cm on day 11 to 1.33±0.08 cm on days 13-17. Injection of the second dose of PGF2α on day 11 of treatment caused rapid decline in the progesterone level from 5.62±0.45 ng/mL on day 10, to 1.09±0.34 ng/mL on day 12, and 0.17±0.05 ng/mL on days 13-17. Estradiol levels were 0.76±0.42, 3.97±1.05 and 5.59±1.36 pg/mL on days 10, 12 and days 13-17. In group 4, the diameter of the largest follicle of the four ovulated buffaloes after first gonadotropin-releasing hormone administration was 1.24±0.09 cm, while that of the unovulated buffalo was 0.97 cm. The diameter of the largest follicle of the ovulated buffaloes was 1.03±0.07 and 1.32±0.03 cm on days 7 and 9 of the treatment. The diameter of the CL was 1.6±0.05 and 1.22±0.07 cm on days 7 and 9 of the treatment. The mean concentration of progesterone level was 1.89±0.56 ng/mL on day 6, 0.27±0.12 ng/mL on day 8 and to 0.04±0.01 ng/mL on day 9 of treatment. The mean concentration of estradiol level was 16.07±9.29, 1.11±0.68 and 2.41±0.93 pg/mL on days 6, 8 and 9 of the treatment.

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

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

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

230 EXPRESSION OF mRNA ENCODING FGF10 AND COGNATE RECEPTORS (FGFR1B AND FGFR2B) AROUND FOLLICLE DEVIATION IN NELORE HEIFERS

2010 ◽  
Vol 22 (1) ◽  
pp. 273
Author(s):  
A. C. S. Castilho ◽  
M. F. Machado ◽  
D. M. Guerra ◽  
R. Ereno ◽  
C. M. Barros ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Granulosa Cells ◽  
Rna Extraction ◽  
Bos Indicus ◽  
Mrna Abundance ◽  
Morphological Divergence ◽  
Dominant Follicle ◽  
Ultrasound Monitoring ◽  
Follicle Diameter ◽  
Follicle Selection

A member of the FGF7 subfamily, FGF10 acts via FGFR2B and FGFR1B. In bovine antral follicles, FGF-10 was detected in oocytes and theca cells (TC). Levels of mRNA were negatively correlated with intrafollicular concentrations of estradiol, and FGF10 inhibited estradiol production from granulosa cells (GC). In Nellore (Bos indicus), morphological divergence occurs on average 2.5 days after ovulation, when dominant follicle diameter is around 6.0 mm. To gain insight into the involvement of the FGF10 system in the control of follicle selection, we assessed mRNA expression of FGF10 in TC and of FGFR1B and FGFR2B in GC from dominant and subordinate follicles around deviation in Nellore heifers. Thirteen Nellore heifers were hormonally synchronized, and ovulation was detected by ultrasound monitoring every 12 h. Heifers were slaughtered 2 (n =4), 2.5 (n = 5), and 3 (n = 4) days after ovulation. Granulosa cells and TC were separated from the 2 largest follicles and submitted to total RNA extraction. mRNA abundance of CYP19 (aromatase), FGF10, FGFR1B, and FGFR2B was measured by real-time RT-PCR and normalized by the expression of cyclophilin A (CYCA) and GAPDH, for TC and GC, respectively. Dominant and subordinate follicles were considered those expressing the greatest and second-greatest abundance of CYP19 mRNA in GC within each heifer. Effects of follicle status and day on CYP19, FGF10, FGFR2B, and FGFR1B mRNA abundance were tested by ANOVA. On Day 2, FGFR2B mRNA abundance was greater in GC of subordinate follicles compared with dominant follicles (P = 0.006), and that of FGF10 in TC tended to exhibit the same pattern (P = 0.06). Follicle diameter was not different between dominant and subordinate follicles on Day 2 (5.5 ± 0 v. 5.12 ± 0.3 cm). On Day 2.5, FGF10 expression was greater in TC from subordinate follicles (P = 0.01), and FGFR2B expression in GC was no longer different between dominant and subordinate follicles. Follicle diameter was greater in dominant follicles on Day 2.5 (6.7 ± 0.2 v. 5.8 ± 0.3 cm; P = 0.04). On Day 3, no differences were observed between dominant and subordinate follicles for any of the genes assessed. mRNA expression of FGFR1B in GC did not change with follicle status or day. In conclusion, expression of FGF10 and FGFR2B was decreased in dominant follicles around morphological divergence, suggesting their involvement in the mechanisms controlling dominant follicle selection. As FGF10 inhibits estradiol production of GC, we propose that FGF10 and FGFR2B are suppressed in the dominant follicle to allow acquisition of full steroidogenic capacity. This research was supported by FAPESP.

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