β-Nerve growth factor is a major component of alpaca seminal plasma and induces ovulation in female alpacas

2012 ◽  
Vol 24 (8) ◽  
pp. 1093 ◽  
Author(s):  
C. M. Kershaw-Young ◽  
X. Druart ◽  
J. Vaughan ◽  
W. M. C. Maxwell

Ovulation in camelids is induced by an unidentified protein in the seminal plasma of the male termed ‘ovulation-inducing factor’. This protein has been reported to be a 14-kDa protein under reducing conditions, which, when purified from seminal plasma, induces ovulation in llamas. The identification of this protein and investigation of its potential to induce ovulation in camelids may aid the development of protocols for the induction of ovulation. In the present study, alpaca seminal plasma proteins were separated using one-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis and the most abundant protein of 14 kDa was identified as β-nerve growth factor (β-NGF) by liquid chromatography mass spectrometry. Female alpacas (n = 5 per group) were given intramuscular injections of: (1) 1 mL of 0.9% saline; (2) 4 µg buserelin, a gonadotrophin-releasing hormone agonist; (3) 2 mL alpaca seminal plasma; or (4) 1 mg human β-NGF. Ovulation was detected by transrectal ultrasonography 8 days after treatment and confirmed by plasma progesterone concentrations. Ovulation occurred in 0%, 80%, 80% and 80% of animals treated with saline, buserelin, seminal plasma and β-NGF, respectively. Treatment type did not affect the diameter of the corpus luteum, but plasma progesterone concentrations were lower in saline-treated animals than in the other treatment groups owing to the lack of a corpus luteum. The present study is the first to identify the ovulation-inducing factor protein in alpacas. β-NGF successfully induces ovulation in alpacas and this finding may lead to new methods for the induction of ovulation in camelids.

2015 ◽  
Vol 27 (8) ◽  
pp. 1181 ◽  
Author(s):  
C. C. Stuart ◽  
J. L. Vaughan ◽  
C. M. Kershaw-Young ◽  
J. Wilkinson ◽  
R. Bathgate ◽  
...  

Ovulation in camelids is induced by the seminal plasma protein ovulation-inducing factor (OIF), recently identified as β-nerve growth factor (β-NGF). The present study measured the total protein concentration in alpaca seminal plasma using a bicinchoninic acid (BCA) protein quantification assay and found it to be 22.2 ± 2.0 mg mL–1. To measure the effects of varying doses of β-NGF on the incidence and timing of ovulation, corpus luteum (CL) size and plasma progesterone concentration, 24 female alpacas were synchronised and treated with either: (1) 1 mL 0.9% saline (n = 5); (2) 4 µg buserelin (n = 5); (3) 1 mg β-NGF protein (n = 5); (4) 0.1 mg β-NGF (n = 5); or (5) 0.01 mg β-NGF (n = 4). Females were examined by transrectal ultrasonography at 1–2-h intervals between 20 and 45 h after treatment or until ovulation occurred, as well as on Day 8 to observe the size of the CL, at which time blood was collected to measure plasma progesterone concentrations. Ovulation was detected in 0/5, 5/5, 5/5, 3/5 and 0/4 female alpacas treated with saline, buserelin, 1, 0.1 and 0.01 mg β-NGF, respectively. Mean ovulation interval (P = 0.76), CL diameter (P = 0.96) and plasma progesterone concentration (P = 0.96) did not differ between treatments. Mean ovulation interval overall was 26.2 ± 1.0 h. In conclusion, buserelin and 1 mg β-NGF are equally effective at inducing ovulation in female alpacas, but at doses ≤0.1 mg, β-NGF is not a reliable method for the induction of ovulation.


2018 ◽  
Vol 106 ◽  
pp. 30-38 ◽  
Author(s):  
Jamie L. Stewart ◽  
Vitor R.G. Mercadante ◽  
Nicholas W. Dias ◽  
Igor F. Canisso ◽  
Peter Yau ◽  
...  

2017 ◽  
Vol 29 (1) ◽  
pp. 114
Author(s):  
J. L. Stewart ◽  
V. R. G. Mercadante ◽  
I. F. Canisso ◽  
F. S. Lima

Nerve growth factor-β (NGF) has been identified in the seminal plasma of livestock and is required for the induction of ovulation in camelids. Until recently, it was thought to play a negligible role in species with spontaneous ovulation. On the contrary, recent studies have shown that systemic administration of NGF, purified from llama seminal plasma, was associated with larger corpus luteum (CL) diameter and higher concentrations of progesterone (P) following ovulation. The objective of the current project was to determine if systemic administration of NGF, purified from bovine seminal plasma, would improve CL formation and enhance embryonic development. Our hypothesis was that systemic administration of NGF at the time of artificial insemination in cows would lead to increased CL volume, increased P secretion, and improved expression of markers of conceptus development and maternal recognition of pregnancy. Seminal plasma was harvested from semen collected by electroejaculation in Angus cross bulls. Purification of NGF was performed using a combination of anion- and cation-exchange chromatography and gradient elution. Beef cows were randomly assigned to CONT (n = 30) or NGF (n = 30) groups and synchronized using a 7-day Co-Synch + CIDR program. At time of insemination (day 0), NGF cows received 296 µg of purified NGF, reconstituted in 12 mL of PBS, and CONT cows received 12 mL of PBS intramuscularly. Blood samples were collected from the coccygeal vein of each cow at days 0, 3, 7, 10, 14, 19, 21, 28, 31, 38, 45, and 66. Ultrasound was performed at each time point for determination of ovarian structures (day 0), corpus luteum volume (all time points), and fetus detection (day 28). Statistical analysis was performed using analysis of variance with repeated-measures in R (R version 3.2.2; https://www.r-project.org/). At day 28, 17/30 (57%) CONT cows and 21/30 (70%) NGF cows were diagnosed as pregnant (P = 0.15). At day 0, cows that later became pregnant had a larger follicular diameter (1.46 cm) than those diagnosed as open (1.16 cm; P < 0.01). Follicular diameter at day 0 did not differ significantly between CONT and NGF groups for either open (P = 0.35) or pregnant (P = 0.90) cows. CL volume in open cows was affected by day (P < 0.001) with no treatment (P = 0.84) or treatment by day (P = 0.42) interaction. CL volume in pregnant cows was affected by both day (P < 0.001) and treatment (P < 0.001), with CONT cows having a higher CL volume than NGF cows. Though NGF appeared to have an inhibitory effect on CL volume in pregnant cows, results are still pending for quantification of P, insulin-like growth factor 1, pregnancy-specific protein B, and interferon-stimulated genes, which will more accurately assess the effects that NGF may have on conceptus development. The results of this study will help us to better understand the role of the seminal plasma protein, NGF, at ovulation and determine if it can be utilised to enhance insemination programs in cattle.


2017 ◽  
Vol 17 (2) ◽  
pp. 442-453 ◽  
Author(s):  
Rosa M. Garcia-Garcia ◽  
Maria del Mar Masdeu ◽  
Ana Sanchez Rodriguez ◽  
Pilar Millan ◽  
Maria Arias-Alvarez ◽  
...  

2021 ◽  
Vol 33 (2) ◽  
pp. 152
Author(s):  
R. A. Carrasco ◽  
S. Pezo ◽  
G. P. Adams

The central inhibitory effects of progesterone on gonadotrophin secretion have been well documented in several species, including camelids. Nerve growth factor (NGF) in seminal plasma triggers ovulation in camelids and is thought to act at the level of the hypothalamus. The objective of the study was to determine the effect of progesterone on NGF-induced LH release in llamas. In Experiment 1, llamas were assigned to a low, medium, or high progesterone group (n=4 per group). The low progesterone group consisted of non-mated (non-ovulatory) llamas, the medium progesterone group consisted of mated llamas (luteal phase; 3–4 weeks pregnant), and the high progesterone group consisted of non-mated llamas given a single intramuscular (IM) dose of progesterone (300mg IM, Progesterone BioRelease LA). A jugular catheter was placed, and the following day llamas were given an intravenous dose of 1mg of NGF isolated from seminal plasma. Blood samples were taken every 30min from 1h before to 5.5h after NGF treatment. In Experiment 2, the pituitary LH response to gonadotrophin-releasing hormone (GnRH) was compared between llamas treated with either Progesterone BioRelease LA or saline (n=4 per group). Sixteen hours later, llamas in both groups were given 50µg of gonadorelin (GnRH) IV, and blood samples were collected by jugular puncture at 0.5h before and 0, 1, 2, and 4h after GnRH. Blood samples were centrifuged, and plasma was stored frozen until radioimmunoassay for LH and progesterone. Data are presented as mean±s.e.m. Data were analysed by one-way ANOVA for single-point and repeated-measures, and independent or paired t-tests. In Experiment 1, plasma progesterone concentrations in the low, medium, and high progesterone groups were 0.6±0.3, 8.2±0.4, and 14.9±1.2ng mL−1, respectively, at the time of NGF treatment (P&lt;0.05). Circulating concentrations of LH did not differ among progesterone groups (treatment, P=0.49; time, P&lt;0.01; treatment×time interaction, P=0.65). In all groups, LH concentrations were elevated within 30min of NGF administration, reached a peak by 2h, and remained elevated beyond the sampling period. Comparison of samples collected during the pretreatment period (i.e. −60, −30, and 0min), however, revealed that plasma LH concentrations in the high progesterone group were half that of the low and medium progesterone groups (P&lt;0.03). In Experiment 2, plasma progesterone concentrations in the progesterone- and saline-treated groups were 12.7±2.2 and 1.3±0.3ngmL−1, respectively (P&lt;0.01). Despite the difference in circulating progesterone concentrations, the LH response to GnRH treatment was not different between groups (treatment group, P=0.43; time, P&lt;0.01; treatment×time interaction, P=0.84). Results demonstrate a suppressive effect of progesterone on basal LH release in llamas, but no suppressive effect on NGF- or GnRH-induced surge release from the pituitary gland. Results are consistent with the hypothesis that the site of action of NGF is downstream of the hypothalamic site of action of progesterone. This research was supported by NSERC Canada.


2018 ◽  
Vol 197 ◽  
pp. 335-342 ◽  
Author(s):  
Jamie L. Stewart ◽  
Igor F. Canisso ◽  
Robyn E. Ellerbrock ◽  
Vitor R.G. Mercadante ◽  
Fabio S. Lima

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