Kisspeptin-54 stimulates the hypothalamic-pituitary gonadal axis in human males

Context: Mutation of the G protein-coupled receptor 54 is associated with a failure of reproductive function. The endogenous neuropeptide agonist for G protein-coupled receptor 54, kisspeptin, potently stimulates the hypothalamic-pituitary-gonadal axis in rodents and primates. Objective: The present study was designed to determine the effects of elevating circulating kisspeptin levels on LH, FSH, and testosterone in male volunteers. Design: This was a double-blind, placebo-controlled, crossover study. Setting: This was a hospital-based study. Participants: Male volunteers (n = 6) were recruited. Interventions: Each volunteer received a 90-min iv infusion of kisspeptin-54 (4 pmol/kg(.)min) and a control infusion of saline (0.9%) in random order. Main Outcome Measure: Plasma LH, FSH, and testosterone concentrations were measured. Results: Kisspeptin-54 infusion significantly increased plasma LH, FSH, and testosterone concentrations compared with saline infusion (mean 90-min LH: kisspeptin, 10.8 +/- 1.5 vs. saline, 4.2 +/- 0.5 U/liter, P < 0.001; mean 90-min FSH: kisspeptin, 3.9 +/- 0.7 vs. saline, 3.2 +/- 0.6 U/liter, P < 0.001; mean 180-min testosterone: kisspeptin, 24.9 +/- 1.7 vs. saline, 21.7 +/- 2.2 nmol/ liter, P < 0.001). The plasma half- life of kisspeptin-54 was calculated to be 27.6 +/- 1.1 min. The mean metabolic clearance rate was 3.2 +/- 0.2 ml/kg(.)min, and the volume of distribution was 128.9 +/- 12.5 ml/kg. Conclusion: Elevation of plasma concentrations of kisspeptin in human males significantly increases circulating LH, FSH, and testosterone levels. Kisspeptin infusion provides a novel mechanism for hypothalamic-pituitary-gonadal axis manipulation in disorders of the reproductive system.