Resulted in 2 distinct protein SIS3 mechanism of action Fractions (Fractions C1 and C2). An

Resulted in 2 distinct protein SIS3 mechanism of action Fractions (Fractions C1 and C2). An in
Resulted in 2 distinct protein fractions (Fractions C1 and C2). An in vivo bioassay (n = 10 to 11 llamas per group) was used to determine the ovarian effect of PubMed ID: each fraction involving treatment with saline (negative control), whole seminal plasma (positive control), or seminal plasma Fractions A, B or C2. Ultrasonography was done to detect ovulation and CL formation, and blood samples were taken to measure plasma progesterone and LH concentrations. Results: Ovulation and CL formation was detected in 0/10, 10/11, 0/10, 2/11, and 10/11 llamas PubMed ID: treated with saline, whole seminal plasma, Fractions A, B and C2 respectively (P < 0.001). A surge in circulating concentrations of LH was detected within 2 hours only in llamas treated with either whole seminal plasma or Fraction C2. Plasma progesterone concentration and CL diameter profiles were greatest (P < 0.05) in llamas treated with Fraction C2. Conclusion: Ovulation-inducing factor was isolated from llama seminal plasma as a 14 kDa protein molecule that elicits a preovulatory LH surge followed by ovulation and CL formation in llamas, suggesting an endocrine effect at the level of the hypothalamus (release of GnRH) or the pituitary (gonadotrophs).Background Historically, the role of seminal plasma has been attributed primarily to its direct effects on spermatozoa; i.e., buffering, nutrition, capacitation, and transport [1]. However, recent findings about the systemic effects of seminal plasma in the female suggest an additional role as an inducer of ovulation. The first direct evidence of an ovulation-inducing factor (OIF) in semen came from workers in China who reported that ovulation occurred after intravaginal or intramuscular administration of Bactrian seminal plasma to female Bactrian camels [2-4].* Correspondence: [email protected] 4 Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Canada Full list of author information is available at the end of the articleThe existence of the putative OIF garnered little scientific attention for 20 years, until it was confirmed in a series of studies involving llamas and alpacas, New World relatives of camels [5]. Results from this and subsequent studies document that OIF 1) exists in semen of alpacas, llamas and koalas (induced ovulators), 2) is a potent stimulator of LH secretion, 3) has a dose-dependent effect on ovulation rate and CL form and function, and 4) acts via a systemic rather than a local pathway, at physiologically relevant doses [5-9]. The discovery of OIF in seminal plasma was made in species categorized as induced ovulators since factors influencing the occurrence of ovulation can be studied without the confounding effects of spontaneous ovulation. Results of recent studies, however, support the?2011 Ratto et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Ratto et al. Reproductive Biology and Endocrinology 2011, 9:24 2 ofhypothesis that OIF in seminal plasma is conserved among species, including those considered to be spontaneous ovulators (e.g., bovine, equine and porcine; [8,10]). Furthermore, OIF in seminal plasma influenced ovarian function in species considered to be spontaneous ovulators; i.e., it in.