Leptin is a hormone secreted by adipocytes with an important role in the control of feeding behavior and neuroendocrine function. Leptin stimulates in vivo LH secretion in fasted female rats and in vitro PRL secretion. Recent data indicate that leptin 116–130, an active fragment of the native molecule, exerts effects similar to those of the native peptide on body weight and food intake. The present study was carried out to determine whether this fragment is also able to stimulate LH and PRL secretion. Adult male rats fasted for 5 days were injected with saline or leptin 116–130 (15 µg icv) and LH and PRL concentrations were measured thereafter at 15-min intervals during a 150-min period. Administration of leptin 116–130 increased the frequency of LH pulses (2.0±0.26 vs. 1.20±0.37/150 min; p≤ 0.05), mean LH levels (0.24±0.06 vs. 0.07±0.03 ng/ml; p≤ 0.05), LH pulse amplitude (0.33±0.10 vs. 0.10±0.05 ng/ml; p≤ 0.05) and the net LH secretion estimated by area under curve (AUC: 36±8.5 vs. 9±3.9 ng/ml/150 min; p≤ 0.01). In addition leptin 116–130 increased the frequency of PRL pulses (2.83±0.48 vs. 1.33±0.21/150 min; p≤ 0.05), trough PRL levels (5.71±0.99 vs. 2.72±0.32 ng/ml; p≤ 0.01), mean PRL levels (13.02±0.92 vs. 5.89±0.51 ng/ml; p≤ 0.01) and net PRL secretion (AUC: 1,625±171 vs. 658±46 ng/ml/150 min; p≤ 0.05). In conclusion, these data show that leptin 116–130 stimulates LH and PRL secretion in fasted adult male rats.