Kisspeptina en becerras prepúberes: 2. Respuesta de LH, FSH y GH a distintas dosis de kisspeptina-10 y su asociación con IGF-I y leptina circulantes

In prepubertal heifers, kisspeptin-10 (KISS-10) stimulates the release of the luteinizing hormone (LH) and the follicle-stimulating hormone (FSH) but the growth hormone (GH) response is inconsistent. The hypothesis of this study was that in prepubertal heifers, the release of LH, FSH and GH in response to KISS-10 is determined by dose and by endogenous levels of IGF-I and leptin. Twenty heifer calves (100-232 kg of body weight and 7-11 mo of age) received an i.v. injection of 5 or 50 µg of KISS-10/kg of body weight (low and high dose, respectively). The high dose of KISS-10 induced a greater ( P 0.05). The magnitude of FSH response as well as GH serum concentrations after KISS-10 were not altered by IGF-I levels ( P >0.05). Similarly, leptin concentrations were not associated ( P >0.05) with the magnitude of LH and FSH response or GH concentrations after KISS-10. In conclusion, GH did not respond to any dose of KISS-10 but FSH and LH were sensitive to an increment in the KISS-10 dose. Additionally, the magnitude of response of LH to KISS-10 was determined by endogenous levels of IGF-I but it was not associated with levels of leptin.