To determine the chemical and functional characterization of an ovulating-inducing factor (OIF) present in the seminal plasma of llamas.

1.- Determine if OIF acts directly at the central level of the Hypothalamic-Pituitary axis using an ovariectomized. 2.- Determine the cellular and tissue localization of OIF in the Hypothalamic-Pituitary axis creating a radiotracer with the incorporation of 125I into the OIF molecule and tracking in vivo binding by autoradiography. 3.- Determine if endogenous or exogenous source of steroids concentration may modulate the stimulatory effect of OIF on LH secretion. 4.- Determine and characterization of the signaling pathways for which OIF elicit LH production and secretion in primary and immortalized pituitary cell cultures. 5.- Compare the effect of Llama OIF to induce LH secretion from induced and spontaneous primary culture of gonadotropes. 6.- Determine the presence and source of production of OIF from induced (rabbit, cats) and spontaneous ovulators (bovine, pig, humans).

The results of this study indicates that OIF induces LH secretion by acting direct or indirectly on the hypothalamic GnRH neurons; however further investigations are necessary to elucidate how OIF reach at the hypothalamus level. The hypothesis that OIF induce LH secretion by acting at the level of hypothalamus was confirmed in a follow up study where biotinylated OIF binds to the rabbits hypothalamus after 15 min of administration while no signals were detected in the hypofisis. An in vivo ovariectomized model was established to determine if estradiol modulates the effect of OIF on LH secretion. According to the results of this study, LH secretion induced by OIF is affected in ovariectomized females (no ovary) as evidenced that its profile was lower than that observed in intact animals (with ovary). When ovariectomized llamas were previously primed with estradiol followed by OIF administration, LH secretion was partly restored close to similar levels detected in intact females (with ovary), suggesting that not only estradiol can modulate the effect of OIF on LH secretion but other ovarian factors may be involved. In addition, this study reinforced the concept that OIF acts at the central level as evidenced that LH secretion occurs regardless ovarian presence.