Blood concentrations of reproductive and metabolic hormones in Merino rams under different feeding regimes: effects of intracerebroventricular administration of recombinant bovine leptin

We infused recombinant bovine leptin (0.4 µg/h/5 days) into the III cerebral ventricle of intact Merino rams fed long-term with either a diet with low content of energy and protein or with a diet rich in energy and protein, to investigate whether leptin is a metabolic signal to the reproductive system. LH pulse frequency was not affected by 5 day of icv infusion of leptin in the groups fed with either a low diet or an high hiet. The results gathered from this study indicate that leptin alone does not represent the nutritional signal to the reproductive axis.