Isolation of Ovulation-inducing Factors in the Seminal Plasma of Bactrian Camel (Camelus bactrianus) by DEAE-cellulose Chromatography

Abstract

Ovulation in the Bactrian camel (Camelus bactrianus) depends upon the ovulation-inducing factor in the seminal plasma; however, little research has been conducted to isolate and identify the factor. The current study attempts to isolate and identify the bioactive fractions from the seminal plasma of Bactrian camel. The seminal plasma was fractionated by diethylamino-ethylcellulose (DEAE)-cellulose chromatography and five protein fractions were obtained. The bioactive of each fraction was estimated by rat pituitary tissue culture in vitro and by the intramuscular injection of the bioactive fraction to the female camels in vivo. The concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the pituitary culture media before and 6 h after the addition of each fraction and in the peripheral blood plasma collected from the camel immediately before and hourly after the injection of the active fraction were measured by radioimmunoassay. The results demonstrated that the third fraction (L3) had the bioactive potential to stimulate the release of LH in vitro from 11.82 +/- 1.77 to 25.63 +/- 3.84 mIU/ml after the addition of L3 to the culture media. The in vivo concentrations of LH in the blood plasma of the camel increased from 6.43 +/- 0.14 before to 15.50 +/- 2.64 ng/ml 6 h after injection of L3. However, the concentrations of FSH did not show any significant changes either in vitro or in vivo. The results clearly demonstrated the existence of LH-releasing associated fractions in the seminal plasma that appears to be separated by DEAE-cellulose matrix and the isolated L3 fraction might be the ovulation-inducing factor or one of its components.

Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma

“…Inconsistencies between our results and in vitro effects of OIF [18-21] require further investigation. A plausible explanation may be related to the OIF concentration used in the in vitro studies.…”

“…In this regard, alpaca seminal plasma induced LH secretion in primary cultures of rat pituitary cells [18]. The same effect has been observed in rat pituitary cultures treated with whole seminal plasma [19] or bioactive fractions isolated from the seminal plasma of Bactrian camels [20,21], a related species where semen-induced ovulation has also been described [22]. Moreover, the addition of anti-GnRH antibodies to the rat pituitary cell cultures did not suppress the effect of alpaca seminal plasma on LH secretion [18], supporting the hypothesis that OIF and GnRH are different molecules affecting LH pituitary secretion in a different manner.…”

Identification of beta-nerve growth factor in dromedary camel seminal plasma and its role in induction of ovulation in females

“…The evidence of an ovulation inducing factor (OIF) has been firstly reported in SP of Bactrian camels (Chen et al, 1985;Pan et al, 2001) and ovulation occurred after intravaginal or intramuscular/intrauterine administration of SP to female Bactrian camels (Zhao et al, 2001;Li and Zhao, 2004). Following studies demonstrated also the presence of this factor in SP of llamas Ratto et al, 2012;Silva et al, 2014) and alpacas Kershaw-Young et al, 2012).…”

Nature, Effects and Possible Mechanisms of Action of Ovulation Inducing Factor: A Review

“…An induced release of LH secretion was reported following treatment of primary cultures of llama and bovine anterior pituitary cells and the magnitude of LH release was proportional to treatment dose (Bogle et al, 2012). Purified OIF or seminal plasma from Bactrian camels or alpacas addition to primary culture of rat pituitary cells caused the secretion of LH (Zhao et al, 2001). Binding with specific (trkA) and non-specific (p75) receptors is involved in effect of OIF/NGF on the hypothalamo-pituitary-ovarian axis.…”