RESUMEN
Ovulation-inducing factor (OIF) is a protein present in llama seminal plasma that has recently been identified as ß-Nerve Growth Factor (NGF) and it induces not only a high rate of ovulation but also appears to have luteotrophic properties in this species. A 2-by-2 experimental design was used to determine the effect of treatments (OIF/NGF vs GnRH) and categories of preovulatory follicle diameter (7-10 vs >10mm) on ovulation rate, CL diameter and function in llamas. Llamas (n=32 llamas per group) were randomly assigned to receive an intramuscular dose of: (a) 1mg purified OIF/NGF in the presence of a follicle of 7-10mm in diameter; (b) 50 µg of GnRH in the presence of a follicle of 7-10mm in diameter; (c) 1mg purified OIF/NGF in the presence of a follicle >10mm in diameter; (d) 50 µg of GnRH in the presence of a follicle >10mm in diameter. Llamas were examined by ultrasonography every 12h from treatment to Day 2 (Day 0=treatment) to detect ovulation, and again on Day 8 to determine CL diameter. Ovulation rates did not differ among groups. There was an effect of preovulatory follicle size on Corpus Luteum diameter at Day 8 (P<0.001), however plasma progesterone concentration (n=15/per group) was higher (P<0.05) in the OIF/NGF - than that of the GnRH - treated group by the same day. We conclude that OIF/NGF treatment enhances CL function regardless preovulatory follicle size at the time of treatment.
Asunto(s)
Camélidos del Nuevo Mundo/fisiología , Cuerpo Lúteo/efectos de los fármacos , Factor de Crecimiento Nervioso/aislamiento & purificación , Factor de Crecimiento Nervioso/farmacología , Folículo Ovárico/citología , Semen/química , Animales , Tamaño de la Célula , Cuerpo Lúteo/diagnóstico por imagen , Cuerpo Lúteo/fisiología , Femenino , Fase Folicular , Hormona Liberadora de Gonadotropina/farmacología , Masculino , Folículo Ovárico/diagnóstico por imagen , Ovulación/efectos de los fármacos , Inducción de la Ovulación/métodos , Inducción de la Ovulación/veterinaria , Ultrasonografía , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Beta-nerve growth factor (beta-NGF) is a trophic factor in the nervous system. We aimed to isolate and characterize this protein in view of its potential therapeutic use in neurodegenerative diseases. For purification a two-step ion-exchange procedure was followed. The characterization was performed using separation and immunological techniques, as well as a biological assay. These studies showed that the obtained protein consisted of a mixture of beta-NGF molecules, intact at their NH2-terminal extreme, and molecules which have lost the NH2-terminal octapeptide and exhibit modifications increasing its hydrophobicity. All these molecular species were recognized immunologically and showed biological activity.