The use of GNRH to control follicular development in cows

Fertility after prostaglandin (PG) may be compromised by the variability in timing of oestrus and ovulation, which are in turn influenced by the ovarian follicular status at the time of injection. Gonadotrophin-releasing hormone (GnRH) treatment in the luteal phase a few days before PG can reprogramme and thus synchronise preovulatory follicle development (Wolfenson et al., 1994). A second GnRH treatment can then be given after PG, to further improve the synchrony of ovulation (Pursley et al., 1995). The present experiment was carried out to test the effect of this combined GnRH - PG - GnRH regime on ovarian function and steroid hormone production in dairy cows.

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The use of GNRH to control follicular development in cows

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200592941 ◽

1996 ◽

Vol 1996 ◽

pp. 95-95

Author(s):

A.R. Peters ◽

S.J. Ward ◽

P.J. Gordon ◽

G.E. Mann

Keyword(s):

Dairy Cows ◽

Present Experiment ◽

Luteal Phase ◽

Ovarian Function ◽

Steroid Hormone ◽

Follicular Development ◽

Follicle Development ◽

Preovulatory Follicle ◽

Hormone Production ◽

Gonadotrophin Releasing Hormone

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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

Journal of Endocrinology ◽

10.1677/joe.0.1450479 ◽

1995 ◽

Vol 145 (3) ◽

pp. 479-490 ◽

Cited By ~ 13

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

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Defining the gonadotrophin requirement for the selection of a single dominant follicle in cattle

Reproduction Fertility and Development ◽

10.1071/rd19060 ◽

2020 ◽

Vol 32 (3) ◽

pp. 322 ◽

Cited By ~ 1

Author(s):

Jin G. Gong ◽

Bruce K. Campbell ◽

Robert Webb

Keyword(s):

Major Effect ◽

Follicle Development ◽

Preovulatory Follicle ◽

Ultrasound Scanning ◽

Dominant Follicle ◽

Initial Exposure ◽

Preovulatory Follicles ◽

Gonadotrophin Releasing Hormone ◽

Follicular Response ◽

Selection Of

The aim was to define the pattern and physiological concentrations of FSH and LH required for the selection of a single dominant follicle in mono-ovulatory species. A series of five experiments was carried out using gonadotrophin-releasing hormone agonist-induced hypogonadal heifers. Animals were infused with different patterns of either FSH and/or LH followed by an ovulatory dose of human chorionic gonadotrophin. Follicular response was monitored by ultrasound scanning and blood samples were collected to measure concentrations of FSH, LH, oestradiol and progesterone. The main findings were: (1) physiological concentrations of FSH given as a continuous infusion and for an adequate duration, in the presence of basal LH, with or without LH pulses, are capable of inducing a superovulatory response, (2) initial exposure to FSH followed by LH pulses alone stimulate the development of multiple preovulatory follicles, confirming that ovarian follicles are capable of transferring dependence on gonadotrophins from FSH to LH, (3) while LH pulses appear not to have a major effect on the pattern of preovulatory follicle development, adequate LH pulsatile support is required for full oestradiol synthesis and (4) the duration of initial exposure to FSH and the ability to transfer the dependence from FSH to LH are critical for the selection of a single dominant follicle. In conclusion, this experimental series confirms that the duration of initial exposure to FSH and the ability of the selected follicle to transfer its gonadotrophic dependence from FSH to LH are critical for the selection of a single dominant follicle in cattle.

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Factors affecting folliculogenesis in ruminants

Animal Science ◽

10.1017/s1357729800050293 ◽

1999 ◽

Vol 68 (2) ◽

pp. 257-284 ◽

Cited By ~ 65

Author(s):

R. Webb ◽

R. G. Gosden ◽

E. E. Telfer ◽

R. M. Moor

Keyword(s):

New Technologies ◽

Ovarian Function ◽

Major Gene ◽

Follicular Development ◽

Oocyte Quality ◽

Ovulation Rate ◽

Follicular Growth ◽

Stages Of Development ◽

Hormone Production ◽

Factors Affecting

AbstractThis review addresses the reasons for the lack of progress in the control of superovulation and highlights the importance of understanding the mechanisms underlying follicular development. The present inability to provide large numbers of viable embryos from selected females still restricts genetic improvement, whilst variability in ovarian response to hormones limit the present capacity for increasing reproductive efficiency.Females are born with a large store of eggs which rapidly declines as puberty approaches. If these oocytes are normal then there is scope for increasing the reproductive potential of selected females. Oocytes must reach a certain size before they can complete all stages of development and the final changes that occur late in follicular development. It is likely that oocytes that do not produce specific factors at precise stages of development will not be viable. Hence, it is important to characterize oocyte secreted factors since there are potential indicators of oocyte quality.The mechanisms that determine ovulation rate have still not been fully elucidated. Indeed follicular atresia, the process whereby follicles regress, is still not known. A better understanding of these processes should prove pivotal for the synchronization of follicular growth, for more precise oestrous synchronization and improved superovulatory response.Nutrition can influence a whole range of reproductive parameters however, the pathways through which nutrition acts have not been fully elucidated. Metabolic hormones, particularly insulin and IGFs, appear to interact with gonadotrophins at the level of the gonads. Certainly gonadotropins provide the primary drive for the growth of follicles in the later stages of development and both insulin and IGF-1, possibly IGF-2, synergize with gonadotrophins to stimulate cell proliferation and hormone production. More research is required to determine the effects of other growth factors and their interaction with gonadotropins.There is evidence, particularly from studies with rodents, that steroids can also modulate follicular growth and development, although information is very limited for ruminants. There may be a rôle for oestrogens in synchronizing follicular waves, to aid in oestrous synchronization regimes and for removing the dominant follicle to achieve improved superovulatory responses. However more information is required to determine whether these are feasible approaches.Heritability for litter size is higher in sheep than in cattle. Exogenous gonadotropins are a commercially ineffective means of inducing twinning in sheep and cattle. Although there are differences in circulating gonadotropin concentrations, the mechanism(s) responsible for the high ovulation appear to reside essentially within the ovaries. The locus of the Booroola gene, a major gene for ovulation rate, has been established but not specifically identified. However sheep possessing major genes do provide extremely valuable models for investigating the mechanisms controlling ovulation rate, including a direct contrast to mono-ovulatory species such as cattle.In conclusion, the relationship between oocyte quality, in both healthy follicles and those follicles destined for atresia, must be resolved before the future potential for increasing embryo yield can be predicted. In addition, a greater understanding of the factors affecting folliculogenesis in ruminants should ensure that the full benefits ensuing from the precise control of ovarian function are achieved. The improved use of artificial insemination and embryo transfer that would ensue from a greater understanding of the processes of folliculo genesis, coupled with the new technologies of genome and linkage mapping, should ensure a more rapid rate of genetic gain.

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The antagonistic effect of exogenous LH pulses on FSH-stimulated preovulatory follicle growth in ewes chronically treated with a gonadotrophin-releasing hormone agonist

Journal of Endocrinology ◽

10.1677/joe.0.1270273 ◽

1990 ◽

Vol 127 (2) ◽

pp. 273-283 ◽

Cited By ~ 19

Author(s):

H. M. Picton ◽

C. G. Tsonis ◽

A. S. McNeilly

Keyword(s):

Luteal Phase ◽

Follicular Development ◽

High Amplitude ◽

Follicle Growth ◽

High Concentration ◽

Continuous Administration ◽

Releasing Hormone ◽

Low Concentrations ◽

Gonadotrophin Releasing Hormone ◽

The Mean

ABSTRACT The hypogonadotrophism model induced by the chronic administration of gonadotrophin-releasing hormone (GnRH) agonist was used to investigate the effects of different concentrations of FSH with or without LH pulses on the stimulation of follicular development in the ewe. Continuous administration of an agonist (buserelin) by osmotic minipump to thirty-six Welsh Mountain ewes from the early luteal phase for 5 weeks resulted in a sustained suppression of the plasma concentration of FSH and inhibited the pulsatile release of LH. The inhibition of gonadotrophin secretion was due to the desensitization and/or down-regulation of pituitary gonadotroph function, since the agonist-treated animals showed no response to a challenge of 1 μg GnRH. During week 6 of agonist treatment, ewes were infused with either 4-hourly pulses of ovine LH (9 μg/pulse), low concentrations of ovine FSH (3 μg/h) or high concentrations of FSH (9 μg/h) alone or with 4-hourly pulses of LH. After 5 days of gonadotrophin infusion, there was no difference between the mean number of follicles per ewe from the animals treated with LH alone, low concentrations of FSH with or without LH pulses or the high concentration of FSH alone compared with the mean number of follicles from control ewes on day 8 of the luteal phase. Infusion of the high concentration of FSH alone stimulated the development of an increased number of large oestrogenic follicles (follicles > 2·5 mm in diameter and secreting > 3·7 nmol oestradiol/h in vitro) compared with control ewes. The addition of high-amplitude LH pulses to the infusion of the high concentration of FSH prevented follicles developing beyond 2·5 mm in diameter, but doubled the number of small follicles (≤2·5 mm) present in the ovaries. These results show that normal follicular development can be induced by physiological concentrations of FSH alone in the absence of pulsatile LH release. The addition of high-amplitude LH pulses antagonized this stimulatory effect of FSH on follicle growth in the ewe. Journal of Endocrinology (1990) 127, 273–283

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Effects of treatment with a gonadotrophin-releasing hormone analogue on follicle development in dairy cows fed one of two different diets

BSAP Occasional Publication ◽

10.1017/s0263967x00034108 ◽

2001 ◽

Vol 26 (2) ◽

pp. 451-455

Author(s):

E.C.L. Bleach ◽

C.L. Moore ◽

H.J. Zeale ◽

P.G. Knight

Keyword(s):

Dairy Cows ◽

Luteal Phase ◽

Cycle Length ◽

Crude Protein ◽

Oestrous Cycle ◽

Follicle Development ◽

Releasing Hormone ◽

Ovulatory Follicle ◽

Metabolisable Energy ◽

Phase Length

AbstractFollicle development occurs in two or three waves during the bovine oestrous cycle. Artificially extending the duration of ovulatory follicle dominance influences pregnancy rates in cattle, as does the interval from emergence to oestrus in dairy cows undergoing spontaneous oestrous cycles. The objectives of the presented study were to determine whether the interval from ovulatory follicle emergence to oestrus might be altered by diet and/or gonadotropin-releasing hormone (GnRH) treatment. Lactating primiparous Holstein/Friesian cows (n=21) were randomly allocated to one of two diets at calving (Diet 1, n=ll, DM 480 g/kg, metabolisable energy 12.0 MJ/kg DM crude protein 178 g/kg DM, oil B 48 g/kg DM, neutral detergent fibre 318 g/kg DM and diet 2, n=10, DM 440 g/kg, metabolisable energy 12.1 MJ/kg DM, crude protein 172 g/kg DM, oil B 40 g/kg DM, neutral detergent fibre 300 g/kg DM). From 10 days after observed oestrus (oestrus 1), ovarian follicular and luteal development was monitored by daily transrectal ultrasonography until the subsequent oestrus and ovulation. A GnRH analogue was injected (i.m.; 10 μg) 12 days after oestrus 1 in 6 cows fed diet 1 and 5 cows fed diet 2. Oestrous cycle length was longer (p<0.05) in control cows fed diet 1 than those fed diet 2. Treatment with GnRH increased (p<0.005) cycle length in cows fed diet 2 but not those fed diet 1. Increases in cycle length observed were associated with longer luteal phase length. Follicular phase length was reduced (p<0.05) by GnRH treatment in cows fed diet 1. Ovulatory follicles emerged later (p<0.05) in control cows fed diet 1 than those fed diet 2. GnRH treatment delayed (p<0.01) the emergence of the ovulatory follicle in cows fed diet 2, this delay was associated with an increase (p<0.05) in the incidence of 3 follicle waves in oestrous cycles following GnRH treatment. The interval from emergence of the ovulatory follicle to the subsequent oestrus was similar among the treatment groups. We conclude that treatment with GnRH during the mid-luteal phase may delay the emergence of the ovulatory follicle. However, the response is dependent on diet fed. Where ovulatory follicle emergence is delayed, the interval from emergence to the subsequent oestrus was unaffected since oestrous cycle length is extended.

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ATF6 knockdown decreases apoptosis, arrests the S phase of the cell cycle, and increases steroid hormone production in mouse granulosa cells

AJP Cell Physiology ◽

10.1152/ajpcell.00222.2016 ◽

2017 ◽

Vol 312 (3) ◽

pp. C341-C353 ◽

Cited By ~ 30

Author(s):

Yongjie Xiong ◽

Huatao Chen ◽

Pengfei Lin ◽

Aihua Wang ◽

Lei Wang ◽

...

Keyword(s):

Cell Cycle ◽

Er Stress ◽

Granulosa Cells ◽

Physiological Function ◽

Steroid Hormone ◽

Follicular Development ◽

S Phase ◽

Mrna Levels ◽

Hormone Production ◽

Protein Levels

Activating transcription factor 6 (ATF6), a sensor protein located in the endoplasmic reticulum (ER) membrane, is an important factor in the ER stress signaling pathway. ER stress is known to be involved in folliculogenesis, follicular growth, and ovulation; however, the physiological function of ATF6 in mouse granulosa cells remains largely unknown. The aim of this study was to assess the role of ATF6 in mouse granulosa cells with respect to apoptosis, the cell cycle, and steroid hormone production, as well as several key genes related to follicular development, via RNA interference, immunohistochemical staining, real-time quantitative PCR, Western blotting, flow cytometry, terminal deoxynucleotidyltransferase-mediated deoxy-UTP nick end labeling (TUNEL) assay, and ELISA. Immunohistochemical staining revealed that ATF6 was extensively distributed in the granulosa cells of various ovarian follicles and oocytes in adult female mice. FSH or LH treatment significantly increased ATF6 protein levels in mouse granulosa cells. In the meantime, a recombinant plasmid was used to deplete ATF6 successfully using short hairpin RNA-mediated interference technology, which was verified at both the mRNA and protein levels. Flow cytometry and TUNEL assay analysis indicated that ATF6 depletion decreased apoptosis and arrested the S phase of the cell cycle in mouse granulosa cells. Consistent with these results, p53, caspase-3, B cell lymphoma 2 (Bcl-2)-associated X protein, CCAAT-enhancer-binding protein homologous protein, cyclin A1, cyclin B1, and cyclin D2 mRNA expression decreased, whereas Bcl-2 and glucose-regulated protein 78 kDa mRNA expression increased. Interestingly, ATF6 knockdown obviously increased progesterone and estradiol production in mouse granulosa cells. Cytochrome P450 1b1 ( Cyp1b1) mRNA levels were downregulated, whereas Cyp11a1, steroidogenic acute regulatory, and Cyp19a1 mRNA levels were upregulated, in keeping with the changes in steroid hormones. Furthermore, ATF6 disruption remarkably increased insulin-like growth factor binding protein 4 ( Igfbp4) expression and decreased hyaluronan synthase 2 ( Has2), prostaglandin-endoperoxide synthase 2 ( Ptgs2), and prostaglandin F receptor ( Ptgfr) expression in mouse granulosa cells, which are proteins crucial for follicular development. But, after treating with tunicamycin, the levels of Has2, Ptgs2, and Ptgfr increased relatively, whereas Igfbp4 expression decreased. Collectively, these results imply that ATF6, as a key player in ER stress signaling, may regulate apoptosis, the cell cycle, steroid hormone synthesis, and other modulators related to folliculogenesis in mouse granulosa cells, which may indirectly be involved in the development, ovulation, and atresia of ovarian follicles by affecting the physiological function of granulosa cells. The present study extends our understanding and provides new insights into the physiological significance of ATF6, a key signal transducer of ER stress, in ovarian granulosa cells.

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Dietary unsaturated fatty acids influence preovulatory follicle characteristics in dairy cows

Reproduction ◽

10.1530/rep-07-0556 ◽

2008 ◽

Vol 135 (5) ◽

pp. 683-692 ◽

Cited By ~ 27

Author(s):

M Zachut ◽

A Arieli ◽

H Lehrer ◽

N Argov ◽

U Moallem

Keyword(s):

Fatty Acids ◽

Dairy Cows ◽

Unsaturated Fatty Acids ◽

Ovarian Function ◽

Post Partum ◽

Control Diet ◽

The Other ◽

Preovulatory Follicle ◽

Preovulatory Follicles ◽

Prostaglandin F

Dietary unsaturated fatty acids (UFAs) have been implicated in several reproductive processes in dairy cows through a variety of mechanisms. This study examined the effects of periparturient supplementation of rumen bypass fats low or high in proportion of UFAs (oleic and linoleic) on preovulatory follicle characteristics. Forty-two 256-day pregnant dairy cows were divided into three groups and were fed a control diet (n=14) or supplemented with fats either low (LUFA; n=14) or high (HUFA; n=14) in UFAs. At 14–15 days following behavior estrus, the cows received a prostaglandin F2α injection and 48 h later >7 mm follicles were aspirated. Progesterone (P4), androstenedione (A4), and estradiol (E2) were determined in the follicular fluid. Out of 75 follicles, 37 follicles that were aspirated between 55 and 70 days post partum were regarded as E2-active follicles (E2/P4 ratio >1) and subjected for further analysis. The diameter of preovulatory follicles was greater in cows fed HUFA than in those fed control or LUFA. The concentrations and content of A4 and E2 in follicles and E2/P4 ratio were higher in the HUFA group than in the other two groups. The P450 aromatase mRNA expression in granulosa cells that were collected from the aspirated preovulatory follicles was also higher in the HUFA cows than in the other groups. A significant correlation was observed between E2 concentrations in preovulatory follicles and E2 concentrations in plasma at aspiration. In conclusion, dietary UFA increased the size of and elevated steroid hormones in preovulatory follicles, which may be beneficial to consequent ovarian function.

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Effect of pulsatile infusion of gonadotrophin-releasing hormone on plasma oestradiol-17β concentrations and follicular development during naturally and artificially maintained high levels of plasma progesterone in heifers

Journal of Endocrinology ◽

10.1677/joe.0.1120077 ◽

1987 ◽

Vol 112 (1) ◽

pp. 77-85 ◽

Cited By ~ 8

Author(s):

R. G. Glencross

Keyword(s):

Luteal Phase ◽

Indirect Evidence ◽

Follicular Development ◽

Pulse Frequency ◽

Oestrous Cycle ◽

Plasma Progesterone ◽

Releasing Hormone ◽

Lh Release ◽

Gonadotrophin Releasing Hormone ◽

Plasma Oestradiol

ABSTRACT To stimulate a follicular-phase pattern of pulsatile LH release, gonadotrophin-releasing hormone (GnRH; 5 μg) was infused (i.v.) hourly into heifers for periods of 5–11 days during the luteal phase of the oestrous cycle, and also when plasma progesterone levels were increased artificially by means of a progesterone-releasing intravaginal device. Plasma oestradiol-17β concentrations increased from basal (EEE 2·5 pmol/l) to preovulatory peak levels (20–30 pmol/l) during the first 3 days of GnRH treatment. They were maintained at these values before returning to basal levels within 24 h of cessation of infusion. This response occurred regardless of the source of progesterone (endogenous or administered). Follicular development was observed by ovarian palpation (per rectum) in some heifers at the time of maximum secretion of oestradiol-17β. There was no detectable cervical mucus secretion or oestrous behaviour during these periods of high oestradiol-17β levels and ovulation did not occur. Treatment with GnRH did not affect plasma progesterone concentrations or oestrous cycle length. The study shows that oestradiol-17β secretion and follicular development (and the accompanying oestrus and ovulation) are suppressed during the luteal phase of the cycle by high concentrations of plasma progesterone, and provides strong indirect evidence that such inhibition is associated with a reduction in the pulse frequency of LH release. J. Endocr. (1987) 112, 77–85

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Effects of lactational level on reactivation of ovarian function, and interval from parturition to first visual oestrus and conception in high-producing holstein cows

Animal Science ◽

10.1017/s0003356100004219 ◽

1989 ◽

Vol 49 (1) ◽

pp. 23-28 ◽

Cited By ~ 25

Author(s):

R. O. Harrison ◽

J. W. Young ◽

A. E. Freeman ◽

S. P. Ford

Keyword(s):

Dairy Cows ◽

Dairy Cow ◽

Glucose Concentration ◽

Luteal Phase ◽

Ovarian Function ◽

Post Partum ◽

Beta Hydroxybutyrate ◽

Ovarian Cyclicity ◽

Average Glucose Concentration ◽

Average Glucose

ABSTRACTData were collected on 19 high-producing Holstein dairy cows from day 20 post partum until they were either determined pregnant or reached 150 days post partum. Blood metabolites (progesterone (P4), glucose, beta-hydroxybutyrate (BHBA) and free fatty acids (FFA)) were related to the interval from parturition to first luteal phase, first visual oestrus and conception. Prior to data analysis, cows were divided into two groups based on their 120-day milk production and designated as below herd average (BHA; no. = 9) or above herd average (AHA; no. = 10). Average 120-day milk productions for BHA, AHA and herdmates (no. = 56) were 3932 (s.e. 157), 4841 (s.e. 60) and 4353 (s.e. 96) kg, respectively. Days from parturition to first luteal phase were not different between the BHA and AHA groups (31·7 (s.e. 1·7) and 31·5 (s.e. 6·9), respectively). In contrast, days from parturition to first visual oestrus and to conception oestrus were less for the BHA group than for the AHA group (46·8 (s.e. 4·6) and 76·9 (s.e. 7·5) v. 67·7 (s.e. 5·2) and 102·5 (s.e. 9·2) days, respectively (P < 0·05)). Further, average glucose concentration from day 20 to first luteal phase was higher (P < 0·05) for the BHA group than for the AHA group (64·1 (s.e. 1·6) v. 58·4 (s.e. 1·6) mg/dl). From day 20 to first visual oestrus, plasma glucose concentration increased while BHBA and FFA declined; all three metabolites then remained relatively constant until conception. These data suggest that as the amount of milk a dairy cow produces increases, the interval from parturition to first visual oestrus and conception increases. These data are consistent with a suppression of oestrus behaviour rather than with a delayed interval to ovarian cyclicity.

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