scholarly journals 210INCREASE IN OVULATION RATE AFTER IMMUNIZATION OF MALPURA EWES AGAINST A SYNTHETIC PEPTIDE SEQUENCE OF THE ±-SUBUNIT OF BOVINE INHIBIN

2004 ◽  
Vol 16 (2) ◽  
pp. 226 ◽  
Author(s):  
S.M.K. Naqvi ◽  
P. Palta ◽  
A. Joshi ◽  
R. Gulyani ◽  
V. Paul ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Synthetic Peptide ◽  
Isotonic Saline ◽  
Active Immunization ◽  
Ovulation Rate ◽  
Peptide Sequence ◽  
Corpora Lutea ◽  
Primary Immunization ◽  
High Fecundity ◽  
Α Subunit

Unlike many other breeds of sheep (e.g. Boroola, Romney or Merino) which have high fecundity, the Malpura ewe, an Indian breed of sheep, is marked by an ovulation rate of one and a low incidence of twinning. Active immunization against a number of inhibin-based synthetic peptides has been reported to increase ovulation rates in these high fecundity breeds of sheep. The objective of the present study was to explore the possibility of increasing ovulation rates in Malpura ewes by active immunization against a synthetic peptide replica of the N-terminal sequence of the bovine inhibin. Adult Malpura ewes (n=5) were actively immunized against a synthetic peptide that corresponded to the N-terminus of the α-subunit of bovine inhibin [bIα(1–29)Tyr30]. The peptide was conjugated to ovalbumin, with a peptide-to-ovalbumin ratio of around 20 moles mole−1, to increase its antigenicity. Control ewes (n=5) were immunized against ovalbumin. On the day of primary immunization, 400μg of peptide-ovalbumin conjugate or ovalbumin were dissolved in 1mL of isotonic saline, emulsified with an equal volume of Freund’s complete adjuvant and injected at four sites in each ewe. Following this, boosters 1, 2 and 3 were given on Days 28, 56 and 84, respectively, of the experiment (Day 0=day of primary immunization); boosters were 200μg of peptide-ovalbumin conjugate or ovalbumin dissolved in 1mL of isotonic saline and emulsified with an equal volume of Freund’s incomplete adjuvant. Estrus was synchronized by a double injection schedule of PGF2α (7.5mg Lutalyse, once each on Days 35 and 45). The animals were subsequently allowed to undergo normal cyclicity until the end of the experiment. Ovulation rate was determined by counting the number of corpora lutea observed during laparoscopic examinations approximately 5 days after estrus during three estrous cyles following treatment. The ovulation rate between control and immunized groups was compared by repeated measures ANOVA. Immunization of the Malpura ewes against the synthetic peptide sequence of the α-subunit of bovine inhibin [bIα(1–29)Tyr30] increased ovulation rate over 5-fold compared to that of controls (Table 1). In conclusion, we have shown that inhibin-based fecundity vaccines have the potential of increasing ovulation rates in the Malpura breed of sheep. Table 1

Effect of active immunization of heifers against inhibin on plasma FSH concentrations, ovarian follicular development and ovulation rate

1992 ◽  
Vol 134 (1) ◽  
pp. 11-18 ◽  
Author(s):  
R. G. Glencross ◽  
E. C. L. Bleach ◽  
B. J. McLeod ◽  
A. J. Beard ◽  
P. G. Knight
Keyword(s):  
Synthetic Peptide ◽  
Ovarian Function ◽  
Statistical Significance ◽  
Follicular Development ◽  
Ovarian Response ◽  
Active Immunization ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Α Subunit ◽  
Ovarian Follicular Development

ABSTRACT To study the effects of immunoneutralization of endogenous inhibin on gonadotrophin secretion and ovarian function, prepubertal heifers (n = 6) were actively immunized against a synthetic peptide replica of the N-terminal sequence of bovine inhibin α subunit bIα(1–29)Tyr30) coupled to ovalbumin. In contrast to ovalbumin-immunized controls (n=6), bIα(1–29)Tyr30-immunized heifers had detectable inhibin antibody titres (% binding to 125I-labelled bovine inhibin at 1:2000 dilution of plasma) of 17 ± 3% (s.e.m.) at puberty, rising to 31 ± 5% by the end of the study period 7 months later. Neither age (immunized: 295 ± 8 days; controls: 300 ± 5 days) nor body weight (immunized: 254 ± 13 kg; controls 251 ± 9 kg) at onset of puberty differed between groups. Although the difference did not reach statistical significance, mean plasma FSH concentrations recorded in inhibin-immunized heifers remained 35–40% higher than in controls throughout the 12-week period leading up to puberty (P = 0·14) and during nine successive oestrous cycles studied after puberty (P=0·10). Plasma LH concentrations did not differ between groups at any time during the study. Inhibin immunization had no effect on oestrous cycle length (immunized: 19·8±0·5 days; controls: 19·9±0·5 days). However, in comparison with controls, inhibinimmunized heifers had more medium sized (≥0·5 to <1 cm diameter) follicles during both the preovulatory (95%, P<0·001) and post-ovulatory (110%, P < 0·05 waves of follicular growth and more large (>1 cm diameter) follicles during the preovulatory wave (49%, P<0·05). In addition, the number of corpora lutea observed during the post-ovulatory phase of each cycle was significantly greater in the inhibin-immunized group (43%, P<0·01), as was the recorded incidence of cycles with multiple ovulations (19/56 in the inhibin-immunized group compared with 0/54 in controls; P<0·001). All six inhibinimmunized heifers had at least one cycle with multiple ovulation whereas none of the control heifers did so. These results support the conclusion that immunoneutralization of endogenous inhibin using a synthetic peptide-based vaccine can enhance ovarian follicular development and ovulation rate in heifers. Whether this ovarian response is dependent upon the expected increase in secretion of FSH remains to be established. Journal of Endocrinology (1992) 134, 11–18

Preovulatory follicle development and luteal function in ewes immunized against a synthetic peptide sequence of the α subunit of bovine inhibin

1992 ◽  
Vol 133 (3) ◽  
pp. 413-419 ◽  
Author(s):  
B. J. McLeod ◽  
M. G. Hunter ◽  
E. C. L. Bleach ◽  
R. G. Glencross ◽  
J. H. M. Wrathall
Keyword(s):  
Synthetic Peptide ◽  
Ovulation Rate ◽  
Peptide Sequence ◽  
Corpora Lutea ◽  
Follicle Development ◽  
Preovulatory Follicle ◽  
Α Subunit ◽  
Luteal Function ◽  
The Mean

ABSTRACT Immunization against inhibin consistently results in an increase in ovulation rate in sheep, but the effects that this treatment has on follicle development are unknown. In order to determine the influence of inhibin, parameters of follicle development were assessed in ewes that had been actively immunized against a synthetic peptide homologous to the N-terminal sequence (α1–29, Tyr30) of the a subunit of bovine inhibin, a treatment that neutralizes the biological activity of endogenous inhibin. The final stages of preovulatory follicle development that culminate in ovulation were induced in seasonally anoestrous ewes, and follicles were recovered prior to the predicted time of ovulation. After priming with progestagen, inhibin-immunized and control ewes were treated with gonadotrophin-releasing hormone (GnRH) by continuous infusion (200 ng/h). The ovaries were recovered at slaughter 24 h after the start of GnRH treatment and all follicles ≥ 2·0 mm diameter were dissected out and their capacity to produce oestradiol in vitro was assessed. Further groups of similarly treated animals were blood-sampled daily to determine luteal function following GnRH-induced ovulation. The ovaries were recovered from these ewes at slaughter 10 days after the start of GnRH treatment, the corpora lutea were dissected out and their progesterone content was assessed. There were more (P < 0·01) follicles of 5–6 mm diameter (3·2 ± 0·45 (s.e.m.) compared with 1·1 ± 0·25 follicles/ewe) and more (P < 0·001) follicles of > 6 mm diameter (2·8 ± 0·56 compared with 0·9 ± 0·17 follicles/ewe) in inhibin-immunized than in control ewes. In addition, the mean number of the antral follicles that were oestrogenic was greater (P < 0·05) in immunized than in control ewes (2·8 ± 0·66 compared with 1·3 ± 0·25 follicles/ewe). In animals slaughtered 10 days after the start of GnRH treatment, mean ovulation rate was greater (3·17 ± 0·65 and 1·14 ± 0·14, P < 0·01) in inhibin-immunized ewes. Although there was more (P < 0·01) total luteal tissue/ewe in the immunized group, both the mean weight and progesterone content (ng/mg tissue) of individual corpora lutea were similar between treatment groups. Mean plasma progesterone levels increased earlier and reached higher (P < 0·01) mean concentrations in immunized than in control ewes. These results demonstrate that immunization against inhibin increases the number of preovulatory follicles during the follicular phase, and that steroidogenesis within these follicles and the resultant corpora lutea appears to be normal. Journal of Endocrinology (1992) 133, 413–419

Inhibin immunoneutralization by antibodies raised against synthetic peptide sequences of inhibin α subunit: effects on gonadotrophin concentrations and ovulation rate in sheep

1990 ◽  
Vol 124 (1) ◽  
pp. 167-176 ◽  
Author(s):  
J. H. M. Wrathall ◽  
B. J. McLeod ◽  
R. G. Glencross ◽  
A. J. Beard ◽  
P. G. Knight
Keyword(s):  
Plasma Levels ◽  
Synthetic Peptide ◽  
Plasma Concentrations ◽  
Ovulation Rate ◽  
Control Groups ◽  
Α Subunit ◽  
Blood Samples ◽  
Antigenic Properties ◽  
N Terminus ◽  
The Mean

ABSTRACT Two experiments were conducted to explore the effectiveness of synthetic peptide-based vaccines for active and passive autoimmunization of sheep against inhibin. In the first experiment, adult Romney ewes (n = 20) were actively immunized against a synthetically produced peptide that corresponded to the N-terminus of the α-subunit of bovine inhibin (bIα(1–29)-Tyr30). This peptide was conjugated to tuberculin purified protein derivative (PPD) to increase its antigenic properties. Control groups comprised non-immunized (n = 10) and PPD-immunized (n = 10) ewes. Primary immunization (400 μg conjugate/ewe) was followed by two booster immunizations (200 μg conjugate/ewe), given 5 and 8 weeks later. Following synchronization of oestrus using progestagen sponges, ovulation rates were assessed by laparoscopy. Weekly blood samples were taken throughout the experiment. All inhibin-immunized ewes produced antibodies which bound 125I-labelled bovine inhibin (Mr 32 000), and ovulation rate in inhibin-immunized ewes (2·15 ± 0·22; mean ± s.e.m.) was significantly (P<0·01) greater than in both non-immunized (0·90 ± 0·23) and PPD-immunized (1·20 ± 0·13) control groups. Immunization against the peptide, but not against PPD alone, resulted in a modest rise in plasma FSH, with mean levels after the second boost being significantly (P<0·025) higher (22%) than those before immunization. Moreover, when blood samples were taken (2-h intervals) from randomly selected groups of control (n = 7) and inhibin-immunized (n = 7) ewes for an 84-h period following withdrawal of progestagen sponges, the mean plasma concentration of FSH during the 48 h immediately before the preovulatory LH surge was 37% greater (P< 0·025) in immunized than in control animals. However, more frequent blood sampling (every 15 min for 12 h) during follicular and mid-luteal phases of the oestrous cycle revealed no significant differences between treatment groups in mean plasma concentrations of FSH. In addition, neither mean concentrations of LH nor the frequency and amplitude of LH episodes differed between immunized and control ewes. However, the mean response of LH to a 2 μg bolus of gonadotrophin-releasing hormone, given during the luteal phase, was significantly (P<0·05) less in immunized than in control ewes. These findings indicate that active immunization of Romney ewes against a synthetic fragment of inhibin can promote a controlled increase in ovulation rate, but this response cannot be unequivocally related to an increase in plasma levels of FSH. In the second experiment, passive immunization of seasonally anoestrous ewes (mule × Suffolk crossbred; n = 6 per group) against inhibin, using an antiserum raised in sheep against a synthetic peptide corresponding to the N-terminus of the α-subunit of human inhibin promoted a rapid (<3 h), dose-dependent rise in plasma levels of FSH which remained increased (2·5-fold; P<0·001) for up to 30 h. Plasma concentrations of LH, however, were unaffected by treatment with the antiserum. It is deduced from this observation that, even in the seasonally anoestrous ewe, the ovary secretes physiologically active levels of inhibin, which exert an inhibitory action on the synthesis and secretion of FSH. Journal of Endocrinology (1990) 124, 167–176

Increased ovulation rate in Merino ewes immunized against small synthetic peptide fragments of the inhibin α subunit

1998 ◽  
Vol 10 (5) ◽  
pp. 421 ◽  
Author(s):  
S. T. Anderson ◽  
B. M. Bindon ◽  
M. A. Hillard ◽  
T. O'Shea
Keyword(s):  
Synthetic Peptides ◽  
Extended Period ◽  
Fold Increase ◽  
Ovulation Rate ◽  
Blood Sampling ◽  
Primary Immunization ◽  
Long Term Effects ◽  
Α Subunit ◽  
Booster Immunization ◽  
Antibody Titres

Four experiments were carried out in Merino ewes during a period of 4 years to determine the long-term effects of immunization against different synthetic peptides mimicking the amine terminal of the a subunit of porcine inhibin. Peptides were conjugated to human serum albumin and 100–200 g emulsified in Freund’s complete adjuvant for the primary immunization. Usually two booster injections were given at monthly intervals with 50–100 g conjugated peptide using either incomplete Freund’s adjuvant or Montanide : Marcol. In some experiments a further immunization was carried in the next year. Blood samples were taken 10 days after each immunization, during the luteal phase, for estimation of gonadotrophin concentrations and determination of inhibin antibody titres. One day after blood sampling cloprostenol was used to induce luteolysis and laparoscopy was performed in the subsequent oestrous cycle. Immunization of ewes with synthetic peptides 1–32, 1–26, 7–26 and 8–30 resulted in large increases in the ovulation rate (OR). An approximately two-fold increase in OR was observed following the first booster immunization with these peptides and a three- to five-fold increase after the second booster immunization. Immunization with these large peptides resulted in a sustained increase in OR for a period of at least 1 year after the second booster immunization. Of the shorter peptides, peptides 10–26 and 13–26 gave a reasonable ovulatory response, although it was more difficult to obtain a response with peptides 1–16, 8–22, 13–25, 8–19 and 10–19; peptides 7–13 and 1–6 gave no response (but were examined for one breeding season only). The smaller peptides led to lower inhibin antibody titres that were not necessarily associated with increased follicle-stimulating hormone (FSH) or OR. More intensive blood sampling in one experiment showed that following primary immunization against peptide 1–32 there was a transient increase in plasma FSH, which did not lead to an increased OR. Moreover, a prolonged period of raised FSH after the first booster was significantly correlated with increased OR. In these animals antibody titres were only slightly increased after primary immunization, but after the first booster immunization higher titres were observed that were significantly correlated with trough FSH values and the subsequent OR. These results are interpreted as showing that (1) to obtain an increase in OR peptides 1–32, 1–26 and 7–26 are suitable as immunogens; (2) smaller peptides are less reliable, often require multiple injections, and the response may be delayed; and (3) an extended period of raised plasma FSH is needed to give a large ovulatory response.

Active immunization of Merino ewe lambs with recombinant bovine alpha inhibin advances puberty and increases ovulation rate

1993 ◽  
Vol 5 (2) ◽  
pp. 173 ◽  
Author(s):  
T O'Shea ◽  
BM Bindon ◽  
RG Forage ◽  
JK Findlay ◽  
CG Tsonis
Keyword(s):  
Monoclonal Antibody ◽  
Follicle Stimulating Hormone ◽  
Plasma Concentrations ◽  
Active Immunization ◽  
Ovulation Rate ◽  
Control Group ◽  
Absolute Amount ◽  
Primary Immunization ◽  
Booster Immunization ◽  
Ewe Lambs

Ewe lambs (n = 24-25) were immunized at 3, 7 and 15 weeks of age with recombinant bovine alpha-inhibin (rec inhibin) or with bovine monoclonal antibody purified inhibin (bMPI) obtained by immunochromatography from bovine follicular fluid or with adjuvant alone (control). Antibodies in the plasma of the lambs immunized with the inhibin preparations bound to iodinated 31 kDa bovine inhibin. Binding was minimal after the primary immunization, increased after each booster immunization and remained elevated until at least 45 weeks of age (29% for rec inhibin and 11% for bMPI). Of the group treated with rec inhibin, 10 ovulated as lambs (control 0/22; bMPI 3/21) and onset of overt oestrous activity (as hoggets) was advanced (P < 0.05) by 17 days in lambs immunized with rec inhibin. As hoggets, the ovulation rate was greater (P < 0.01) in the rec inhibin immunized lambs (4.41 +/- 0.67) than in the control animals (1.27 +/- 0.15) but not in the bMPI-treated lambs (1.40 +/- 0.16). After a further immunization at 17 months of age, however, ovulation rate increased (P < 0.01) in the bMPI-immunized group (3.40 +/- 0.47) but was unchanged in the lambs immunized with rec inhibin (2.80 +/- 0.52) and those in the control group (1.15 +/- 0.08). There were no effects of immunization on plasma concentrations of either follicle stimulating hormone (FSH) or luteinizing hormone (LH). The initial smaller response seen with the bMPI may be due to either the presence of compounds other than inhibin in such preparations or the small absolute amount of inhibin injected.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effect of Immunization against Progesterone on Oestrus, Cycle Length, Ovulation Rate, Luteal Regression and LH Secretion in the Ewe

1987 ◽  
Vol 40 (3) ◽  
pp. 307 ◽  
Author(s):  
GB Thomas ◽  
CM Oldham ◽  
RM Hoskinson ◽  
RJ Scaramuzzi ◽  
GB Martin
Keyword(s):  
Cycle Length ◽  
Reproductive Activity ◽  
Active Immunization ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Luteal Regression ◽  
Oestrus Cycle ◽  
Different Ages ◽  
Lh Secretion

The effects of active immunization against progesterone on reproductive activity were studied in Merino ewes. Immunization against progesterone caused a shortening (P < 0'01) of the interval between ovulations from 17-18 days (controls) to between 6 and 10 days (immunized group); this was associated with a corresponding reduction in the interval between LH surges. The immunized ewes also had higher (P < O� 05) ovulation rates (1' 72) than controls (I. 25) and exhibited a reduced (P < 0'01) incidence of oestrus (26% v. 95%). Many immunized ewes continued to ovulate despite the persistence of corpora lutea from earlier ovulations which led to an accumulation on the ovaries of many corpora lutea of different ages. The frequency of LH pulses in ewes immunized against progesterone (1'8 � 0�2 pulses/4 h) was significantly (P < 0'001) higher than that of control ewes (0'3 � 0�1 pulses/4 h). This study highlights the importance of progesterone in the control of oestrus, ovulation, ovulation rate, luteal regression and the secretion of LH in the ewe.

Increased ovulation and twin-calving rates in heifers immunized against bovine inhibin peptides

1992 ◽  
Vol 1992 ◽  
pp. 43-43
Author(s):  
D.G. Morris ◽  
M.G. Diskin ◽  
J.M. Sreenan
Keyword(s):  
Negative Feedback ◽  
Solid Phase ◽  
Feedback Regulation ◽  
Active Immunization ◽  
Ovulation Rate ◽  
Negative Feedback Regulation ◽  
Α Subunit ◽  
Gonadotrophin Secretion ◽  
Antibody Titres ◽  
Calving Rate

Inhibin is a dimeric protein hormone composed of two dissimilar, disulphide-linked subunits (termed α and β) involved in the negative feedback regulation of gonadotrophin secretion, preferentially FSH. Interfering with this negative feedback by active immunization against inhibin has resulted in a consistent increase in ovulation rate and litter size in sheep. However, similar results have not been achieved in cattle. This paper describes the effect of active immunization of heifers against either of 3 synthetic peptide sequences from the bovine inhibin α-subunit on inhibin antibody titres, ovulation rate, calving rate and twin-calving rate.Three peptide sequences from the bovine inhibin a-subunit were identified as likely immunological epitopes by computer analysis. These peptides (P1: bl-α-[YG] (18-30); P2: bl-α-(63-72)[GY]; P3: bl-α-[CG](107-122) were synthesized by solid phase methods and tyrosyl or cystenyl residues, linked through a glycine spacer where appropriate, were added during synthesis in order to facilitate iodination and conjugation respectively.

scholarly journals A rodent model of human dose-equivalent progestin-only implantable contraception

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Heather C. M. Allaway ◽  
Roger A. Pierson ◽  
Jesse Invik ◽  
Susan A. Bloomfield
Keyword(s):  
Repeated Measures ◽  
Ovarian Function ◽  
Virgin Female ◽  
Rodent Model ◽  
High Dose ◽  
Corpora Lutea ◽  
Average Dose ◽  
Estrus Cycle ◽  
Human Dose ◽  
Dose Dependent

Abstract Background Long-acting, reversible contraceptives (LARC; progestin only) are an increasingly common hormonal contraceptive choice in reproductive aged women looking to suppress ovarian function and menstrual cyclicity. The overall objective was to develop and validate a rodent model of implanted etonogestrel (ENG) LARC, at body size equivalent doses to the average dose received by women during each of the first 3 years of ENG subdermal rod LARC use. Methods Intact, virgin, female Sprague-Dawley rats (16-wk-old) were randomized to 1 of 4 groups (n = 8/group) of ENG LARC (high-0.30μg/d, medium-0.17μg/d, low-0.09μg/d, placebo-0.00μg/d) via a slow-release pellet implanted subcutaneously. Animals were monitored for 21 days before and 29 days following pellet implantation using vaginal smears, ultrasound biomicroscopy (UBM), saphenous blood draws, food consumption, and body weights. Data were analyzed by chi-square, non-parametric, univariate, and repeated measures 2-way ANOVA. Results Prior to pellet implantation there was no difference in time spent in estrus cycle phases among the treatment groups (p > 0.30). Following pellet implantation there was a dose-dependent impact on the time spent in diestrus and estrus (p < 0.05), with the high dose group spending more days in diestrus and fewer days in estrus. Prior to pellet insertion there was not an association between treatment group and estrus cycle classification (p = 0.57) but following pellet implantation there was a dose-dependent association with cycle classification (p < 0.02). Measurements from the UBM (ovarian volume, follicle count, corpora lutea count) indicate an alteration of ovarian function following pellet implantation. Conclusion Assessment of estrus cyclicity indicated a dose-response relationship in the shift to a larger number of acyclic rats and longer in duration spent in the diestrus phase. Therefore, each dose in this model mimics some of the changes observed in the ovaries of women using ENG LARC and provides an opportunity for investigating the impacts on non-reproductive tissues in the future.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

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