Luteotrophic effect of OIF/NGF in llamas

  • Marcelo Ratto Fuster Universidad Austral de Chile


An Ovulation-Inducing Factor (OIF) isolated from llama seminal plasma has recently been identified as Nerve Growth Factor (NGF). This protein not only has a potent ovulatory but also a luteotrophic effect in llamas after intramuscular or intrauterine infusion. The objective of the present review is to summarize the results of the effect of OIF/NGF on Corpus Luteum (CL) development in llamas. The results of a series of experiments demonstrate that the luteotrophic effect of OIF/NGF is mediated by a change in the secretion pattern of the LH surge. The intramuscular administration of OIF/NGF increases progesterone secretion regardless of the size of the preovulatory follicle at the time of treatment. The repeated administration of OIF/NGF during the periovulatory period (preovulatory, ovulatory, early postovulatory) increases CL size, vascularization and progesterone production. The effect of OIF/NGF varies with the route of administration (intramuscular, intravenous and intrauterine). It was concluded that OIF-NGF elicits a preovulatory LH surge followed by ovulation and development of a functional CL, regardless of the route of administration. However, with the intrauterine treatment, a physiological dose of OIF/NGF was required to elicit pituitary and ovarian responses.


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Author Biography

Marcelo Ratto Fuster, Universidad Austral de Chile
Médico Veterinario, Universidad Nacional de La Plata, Argentina, 1986. Master en Ciencias, especialidad: Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Chile, 1994. PhD, Department of Veterinary Biomedical Science, Western College of Veterinary Medicine, University of Saskatchewan, Canada, 2005.
How to Cite
Ratto Fuster, Marcelo. 1. “Luteotrophic Effect of OIF/NGF in Llamas”. Latin American Archives of Animal Production 24 (2).
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